sort is a ruby method that can be performed, so using it will cause confusion for the framework: Did you mean "run the sort method, or sort this object?".
There are a whole heap of these reversed words (some are even hidden). I did see a list somewhere, but cannot find it.
To get around the problem rename the action and create a route to it: map.connect '/ControllerName/search', :controller => 'ControllerName', :action =>'MyNewName'
Are there better ways?