No he encontrado ningún problema al implementar mi proyecto laravel hasta ahora. He estado implementando durante casi un año ya para este proyecto. Pero surgió un nuevo error.

Ante todo. No puedo ejecutar la actualización del compositor, porque dice este error.

composer update
Warning: This development build of composer is over 30 days old. It is recommended to update it by running "/usr/local/bin/composer self-update" to get the latest version.
Loading composer repositories with package information
Updating dependencies (including require-dev)



  [RuntimeException]
  Could not load package classpreloader/classpreloader in http://packagist.org: [UnexpectedValueException] Could not parse version constraint ^1.2.2: Invalid
   version string "^1.2.2"






  [UnexpectedValueException]
  Could not parse version constraint ^1.2.2: Invalid version string "^1.2.2"



update [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--lock] [--no-plugins] [--no-custom-installers] [--no-scripts] [--no-progress] [--with-dependencies] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [packages1] ... [packagesN]

Entonces, lo que hice fue actualizar mi biblioteca Composer.

Esta es mi versión actual

 Composer version 1e27ff5e22df81e3cd0cd36e5fdd4a3c5a031f4a 2014-08-11 15:46:48

Actualicé al compositor.

[api@my staging-hoho-middleware]$ sudo composer self-update^C
[api@my staging-hoho-middleware]$ sudo /usr/local/bin/composer self-update
Updating to version b2173d28fc8b56236eddc8aa10dcda61471633ec.
    Downloading: 100%
Use composer self-update --rollback to return to version 1e27ff5e22df81e3cd0cd36e5fdd4a3c5a031f4a
[api@my staging-hoho-middleware]$ composer update
Loading composer repositories with package information
Updating dependencies (including require-dev)

Pero me encuentro con un nuevo problema una vez que ejecuté la actualización del compositor

[api@my staging-hoho-middleware]$ composer update
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - phpunit/phpunit 4.7.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.7.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.7.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.7.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.9 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.8 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.7 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.6 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.5 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.10 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.6.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.5.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.5.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.4.5 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.4.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.4.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.4.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.4.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.4.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.3.5 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.3.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.3.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.3.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.3.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.3.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.2.6 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.2.5 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.2.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.2.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.2.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.2.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.

     - phpunit/phpunit 4.0.12 requires ext-dom * -> the requested PHP extension dom is missing from your system.                                                                                     [0/1888]
    - phpunit/phpunit 4.0.11 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.0.10 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.0.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 4.0.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.9 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.8 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.7 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.6 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.5 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.38 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.37 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.36 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.35 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.34 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.33 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.32 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.31 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.30 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.29 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.28 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.27 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.26 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.25 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.24 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.23 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.22 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.21 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.20 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.19 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.18 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.17 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.16 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.15 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.14 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.13 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.12 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.11 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.10 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - phpunit/phpunit 3.7.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
    - Installation request for phpunit/phpunit * -> satisfiable by phpunit/phpunit[3.7.0, 3.7.1, 3.7.10, 3.7.11, 3.7.12, 3.7.13, 3.7.14, 3.7.15, 3.7.16, 3.7.17, 3.7.18, 3.7.19, 3.7.2, 3.7.20, 3.7.21, 3.7.
22, 3.7.23, 3.7.24, 3.7.25, 3.7.26, 3.7.27, 3.7.28, 3.7.29, 3.7.3, 3.7.30, 3.7.31, 3.7.32, 3.7.33, 3.7.34, 3.7.35, 3.7.36, 3.7.37, 3.7.38, 3.7.4, 3.7.5, 3.7.6, 3.7.7, 3.7.8, 3.7.9, 4.0.0, 4.0.1, 4.0.10, 4
.0.11, 4.0.12, 4.0.13, 4.0.14, 4.0.15, 4.0.16, 4.0.17, 4.0.18, 4.0.19, 4.0.2, 4.0.20, 4.0.3, 4.0.4, 4.0.5, 4.0.6, 4.0.7, 4.0.8, 4.0.9, 4.1.0, 4.1.1, 4.1.2, 4.1.3, 4.1.4, 4.1.5, 4.1.6, 4.2.0, 4.2.1, 4.2.2,
 4.2.3, 4.2.4, 4.2.5, 4.2.6, 4.3.0, 4.3.1, 4.3.2, 4.3.3, 4.3.4, 4.3.5, 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.4.4, 4.4.5, 4.5.0, 4.5.1, 4.6.0, 4.6.1, 4.6.10, 4.6.2, 4.6.3, 4.6.4, 4.6.5, 4.6.6, 4.6.7, 4.6.8, 4.6.9,
 4.7.0, 4.7.1, 4.7.2, 4.7.3].

Ahora me inclino por desinstalar mi compositor y crear una nueva copia nueva.