MethodNotAllowedHttpException in laravel

I am getting 'Symfony \ Component \ HttpKernel \ Exception \ MethodNotAllowedHttpException' as response when I am trying to check if the validator works. This is my code :

in my view 'addMedia-partial.blade.php' :

         {{ Form::open() }}

            <input type="text" name="videoUrl" placeholder="enter youtube video url" />
            <input type="text" name="videoTitle" placeholder="enter video title" />
            <input type="text" name="videoDescription" placeholder="enter video description" />

            <input type="submit" value="Save">

        {{ Form::close() }}

in my routes.php :

Route::get('/guide/dashboard/media/add/storeVideo', array('as' => 'guide-video-add','uses' => 'MediaController@getNewVideo'));
Route::post('/guide/dashboard/media/add/storeVideo', array('uses' => 'MediaController@postNewVideo'));

in my controller MediaController.php :

public function postNewVideo() 
{

        $rules = array('videoUrl' => 'required', 'videoTitle' => 'required|min:5', 'videoDescription' => 'required|min:20');

        $validator = Validator::make(Input::all(), $rules);

        if ($validator->fails()) {


            //return Redirect::route('guide-media-add')->withErrors($validator);
            //gaat niet omdat dit in een andere controller is ?? 

            return Redirect::route('guide-video-add')->withErrors($validator);

        }
}

public function getNewVideo()
{
    return View::make('guide.dashboard.dashboard')->nest('child', 'guide.dashboard.addMedia-partial');
}