[TYPO3-50-general] Strange uncaught exception

[Julian Kleinhans]

Hi list,

i have a strange problem.

I have a AdvertisementController and a Advertisement Model. The 
Controller has a indexAction, createAction, editAction and a 
updateAction. In the indexAction i have the FLUID form to create a 
Advertisement. Thats no problem, after that i displayed a list ao all 
available Advertisements. Every Row has a Edit link

<f:link.action action="edit" 
arguments="{advertisement:advertisement}">EDIT</f:link.action>	

The result is: 
domain.de/package/advertisement/edit?advertisement[__identity]=7ba702ac-fb94-4903-896d-e14a2856eb3f

The identity is correct!
Ok, my editAction looks like

/**
  * Edit an existing advertisement
  *
  * @param \F3\Package\Domain\Model\Advertisement $advertisement
  * @dontvalidate $advertisement
  */
public function editAction(\F3\Package\Domain\Model\Advertisement 
$advertisement) {
	$this->view->assign('advertisement', $advertisement);
}

So, normaly i must see the edit form but i become a uncaught exception

#1269616784: The value of argument "advertisement" must be of type 
"F3\Package\Domain\Model\Advertisement", but was of type "NULL".


i dont know why.. the URI is in my opinion absolut correct.
And the object exsists!

Any ideas ?

greetz
julian