Use CController::beginContent() to achieve greater control in rendering a layout.
In the function signature (CBaseController documentation), $view refers to the view path:
public void beginContent(mixed $view=NULL, array $data=array ( ))
The beginContent() method uses the CContentDecorator class. The CContentDecorator documentation uses forward slashes to represent path notation:
$this->beginContent('path/to/view');
In fact, Yii dot-notation is required:
$this->beginContent('path.to.view');
Example from a live Yii site:
$this->beginContent('application.views.layouts.admin.main');