Não é possível executar o aplicativo em Grails

Acabei de instalar o Groovy 2.0.1 e o Grails 2.1.0.

Estava seguindo as instruções sobre como criar um aplicativo da web Hello World simples em:

http://grails.org/doc/latest/guide/gettingStarted.html#creatingAnApplication

Quando tentei executar o aplicativo, recebi o seguinte erro:

grails> run-app

| 
Compiling 113 source files
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
    | Running Grails application
    | Error 2012-07-27 17:05:41,773 [pool-4-thread-1] ERROR core.ContainerBase
      - A child        container failed during start
Message: org.apache.catalina.LifecycleException: Failed to start component
   [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[/helloworld]]
    Line | Method
    ->> 222 | innerGet in java.util.concurrent.FutureTask$Sync

Caused by LifecycleException: Failed to start component 
   [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[/helloworld]]
    ->> 303 | innerRun in java.util.concurrent.FutureTask$Sync

Caused by NoSuchMethodError:  
 javax.servlet.ServletContext.getSessionCookieConfig()Ljavax/servlet/SessionCookieConfig;
    ->> 303 | innerRun in java.util.concurrent.FutureTask$Sync
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
    |   138 | run      in java.util.concurrent.FutureTask
    |   886 | runTask  in java.util.concurrent.ThreadPoolExecutor$Worker
    |   908 | run      in     ''
 ^   680 | run . .  in java.lang.Thread
    | Error 2012-07-27 17:05:41,869 [main] ERROR core.ContainerBase
    A child container failed during start

   Message: org.apache.catalina.LifecycleException: Failed to start component
  [StandardEngine[Tomcat].StandardHost[localhost]]
  Line | Method
  ->> 222 | innerGet  in java.util.concurrent.FutureTask$Sync
  |    83 | get       in java.util.concurrent.FutureTask
  |   137 | doStart . in org.grails.plugins.tomcat.InlineExplodedTomcatServer
  |   102 | start     in org.grails.plugins.tomcat.TomcatServer
  |   176 | doCall .  in RunApp$_run_closure5_closure12
  |   153 | doCall    in RunApp$_run_closure5
  |   121 | runInline in RunApp
  |    67 | doCall    in RunApp$_run_closure1
  ^    33 | doCall .  in     ''

  Caused by LifecycleException: Failed to start component
  [StandardEngine[Tomcat].StandardHost[localhost]]
  ->> 303 | innerRun  in java.util.concurrent.FutureTask$Sync

  |   138 | run       in java.util.concurrent.FutureTask
  |   886 | runTask . in java.util.concurrent.ThreadPoolExecutor$Worker
  |   908 | run       in     ''
  ^   680 | run . . . in java.lang.Thread

  Caused by LifecycleException: A child container failed during start
  ->> 303 | innerRun  in java.util.concurrent.FutureTask$Sync

  |   138 | run       in java.util.concurrent.FutureTask
  |   886 | runTask . in java.util.concurrent.ThreadPoolExecutor$Worker
  |   908 | run       in     ''
  ^   680 | run . . . in java.lang.Thread
  | Error Failed to start component [StandardServer[-1]] 
   (NOTE: Stack trace has been filtered. Use --verbose to see entire trace.)
   org.apache.catalina.LifecycleException: Failed to start component [StandardServer[-1]]
at
   org.grails.plugins.tomcat.
      InlineExplodedTomcatServer.doStart(InlineExplodedTomcatServer.groovy:137)
at org.grails.plugins.tomcat.TomcatServer.start(TomcatServer.groovy:102)
at RunApp$_run_closure5_closure12.doCall(RunApp:176)
at RunApp$_run_closure5.doCall(RunApp:153)
at RunApp.runInline(RunApp:121)
at RunApp$_run_closure1.doCall(RunApp:67)
at RunApp$_run_closure1.doCall(RunApp.groovy:33)
  Caused by: org.apache.catalina.LifecycleException: Failed to start component
  [StandardService[Tomcat]]
... 7 more
  Caused by: org.apache.catalina.LifecycleException: Failed to start component
  [StandardEngine[Tomcat]]
... 7 more
  Caused by: org.apache.catalina.LifecycleException: A child container failed during start
... 7 more
  | Error Server failed to start: org.apache.catalina.LifecycleException: Failed to start component [StandardServer[-1]]
  | Error Error running script run-app: org.codehaus.groovy.grails.cli.ScriptExitException
  (Use --stacktrace to see the full trace)

O que estou possivelmente fazendo errado? Este tutorial não especificou para configurar uma configuração para o tomcat em qualquer lugar?