Error when adding a relationship: * warning: Attempt to assign property of non-object in..

When i create a relationship with this link: /relationship/request/UID?destination=user%2FUID

I get this:

    * warning: Attempt to assign property of non-object in E:\wamp\proj\home\modules\user_relationships\user_relationships_actions.inc on line 168.
    * warning: Attempt to assign property of non-object in E:\wamp\proj\home\modules\user_relationships\user_relationships_actions.inc on line 169.
    * warning: Attempt to assign property of non-object in E:\wamp\proj\home\modules\user_relationships\user_relationships_actions.inc on line 170.
    * warning: Attempt to assign property of non-object in E:\wamp\proj\home\modules\user_relationships\user_relationships_api.inc on line 245.
    * warning: Attempt to assign property of non-object in E:\wamp\proj\home\modules\user_relationships\user_relationships_api.inc on line 246.
    * warning: Invalid argument supplied for foreach() in E:\wamp\proj\home\modules\user_relationships\user_relationships_api.inc on line 30.
    * warning: Attempt to assign property of non-object in E:\wamp\proj\home\modules\user_relationships\user_relationships_api.inc on line 247.

And this:
Your request to be a of anonymus has been submitted.

I tryed to put in user_relationships_actions.inc the following line:
drupal_set_message('<pre>'. print_r($relationship, TRUE) .'</pre>');
And i got this:
This relationship already exists
--
My actuals relationship types are:
amico (no implies, mutual, requires approval)
conosciuto dal vivo (implies: "amico", mutual, requires approval)
compagno di scuola (implies: "amico" and "conosciuto dal vivo", mutual, requires approval)
nemico (no implies, one way, doesn't require approval)

Test is "amico" of mine and when i try to add "conosciuto dal vivo" relationship with him i get the "Attempt to assign property of non-object.." etc etc

What i have to do? Please, help me.

Sorry for my bad english :/