Error de SQL en la paginación

Hola chicos, tenemos una página web que funciona perfectamente (index_admin) del controlador de Relaciones, pero después de agregar la paginación, todo se bloquea.

Dar con:

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'Relationship.sender_id' in 'where clause'

Los clientes y las empresas crean "relaciones" para que puedan intercambiar facturas a través de nuestro sitio web. Aquí está el esquema DB:

ID, ID del remitente, ID del receptor, activo, solicitado, fecha de caducidad

Sender_id y receiver_id son claves foráneas para la tabla de cuentas. En otras palabras, le dice al db qué cuentas están vinculadas entre sí.

Modelo de relación 'BELONGSTO' 'MODELOS DE CUENTAS DE RECEPTOR Y DE ENVÍO':

public $belongsTo = array(
        'ReceiverAccount' =>array(
            'className' => 'Account',
            'foreignKey' =>'receiver_id',
            'associationForeignKey'  => 'accounts_id',
            ),
        'SenderAccount' =>array(
            'className' => 'Account',
            'foreignKey' =>'sender_id',
            'associationForeignKey'  => 'accounts_id',)
            ); 

Index_admin:

public function index_admin(){
        $this->set('title_for_layout', 'Relationships');
        $this->set('stylesheet_used', 'homestyle');
        $this->set('image_used', 'eBOXLogoHome.png');   
        $this->layout='home_layout';

        //retrieve Account Id of current User       
        $accountid=$this->Auth->user('account_id');

        //Conditions
        $conditions=array(
        "OR"=> array(
            'Relationship.sender_id' => $accountid,
            'Relationship.receiver_id' => $accountid)
        );



        //Find all Invoices where receiver_id = accountid
        $relationships=$this->Relationship->find('all', array(
        'conditions' => $conditions));

        debug($conditions);

        $compName = $this->Account->field('account_name', array('id' => 'Relationship.id'));

        $this->paginate = array(
        'limit' => 10,
        'conditions'=> $conditions
        );

        $this->set('accountid', $accountid); 
        $this->set('relationship', $this->paginate());  

        $this->set('compName', $compName);  
    }

Vista Index_admin (parcial):

<table id="data">
                <tr>
                        <td colspan=7 align='right'>
                        <?php 
                        echo $this->Paginator->prev('<' . __('previous'), array(), null, array('class'=>'prev disabled'));  
                        echo '&nbsp;';
                        echo $this->Paginator->numbers(array('seperator'=>'')); 
                        echo '&nbsp;';
                        echo $this->Paginator->next(__('next') . '>', array(), null, array('class'=>'next disabled'));
                        ?>
                        </td>
                </tr>
                <tr>
                    <th><?php echo $this->Paginator->sort('id'); ?></th>
                    <th><?php echo $this->Paginator->sort('sender_id'); ?></th>
                    <th><?php echo $this->Paginator->sort('receiver_id'); ?></th>
                    <th><?php echo $this->Paginator->sort('expiry_date'); ?></th>
                    <th>Status</th>
                    <th>Actions</th>
                </tr>

        <?php foreach($relationship as $relationships):?>

        <?php

        if($relationships['Relationship']['requested']==1)
        {
            $status = 'Requested';
            $bgcol = '#F8FAC0';
        }
        else if($relationships['Relationship']['active']==1)
        {
            $status = 'Active';
            $bgcol = '#CFDAE8';
        }
        else if($relationships['Relationship']['active']==0)
        {
            $status = 'Expired';
            $bgcol = '#FAB9B9';
        }       

        if($relationships['Relationship']['active']==0 && $relationships['Relationship']['requested']==0)
        {
            $action = 'Reactivate';
        }
        else
        {
            $action = 'Edit Expiry';
        }

        if($relationships['Relationship']['sender_id']==$accountid)
        {
            $start = '<font color="#191970">';
            $end = '</font>';
        }
        else
        {
            $start = NULL;
            $end = NULL;
        }

        if($relationships['Relationship']['receiver_id']==$accountid)
        {
            $startr = '<font color="#191970">';
            $endr = '</font>';
        }
        else
        {
            $startr = NULL;
            $endr = NULL;
        }


        if($relationships['Relationship']['sender_id']==$accountid)
        {
            $acctname = $relationships['ReceiverAccount']['account_name'];
        }
        else if($relationships['Relationship']['receiver_id']==$accountid)
        {
            $acctname = $relationships['SenderAccount']['account_name'];
        }

?>

                    <tr>
                        <td align='center'><?php echo $relationships['Relationship']['id']; ?></td>
                        <td align='center'><?php echo $start?><?php echo $relationships['SenderAccount']['account_name']; ?><?php echo $end ?></td>
                        <td align='center'><?php echo $startr?><?php echo $relationships['ReceiverAccount']['account_name']; ?><?php echo $endr ?></td>
                        <td align='center'><?php echo date('d.m.Y', strtotime($relationships['Relationship']['expiry_date'])); ?></td>
                        <td align='center' bgcolor='<?php echo $bgcol ?>'><?php echo $status ?></td>
                        <td align='center'> 
                        <?php echo $this->Form->Html->link('Delete', array('controller' => 'Relationships','action'=>'delete',$relationships['Relationship']['id']), NULL, 'Are you sure you want to delete '. $acctname);
                         ?> | <?php echo $action ?> </td>
                    </tr>
                <?php endforeach; ?>

            <tr>
                        <td colspan=7 align='right'>
                        <?php 
                        echo $this->Paginator->prev('<' . __('previous'), array(), null, array('class'=>'prev disabled'));  
                        echo '&nbsp;';
                        echo $this->Paginator->numbers(array('seperator'=>'')); 
                        echo '&nbsp;';
                        echo $this->Paginator->next(__('next') . '>', array(), null, array('class'=>'next disabled'));
                        ?>
                        </td>
            </tr>
            </table>

Como dije, todo estaba funcionando antes, ahora no, pero no puedo ver por qué.