Polylang not saving menu lenguage settings

Hello, I have a really strange Problem. I am working on a WordPress Multisite installation with 2 sites on wp version 3.5.1 with polylang version 1.0.1 and 3 languages. Everything worked fine, including the update. Then, one of our moderators accidently deleted a menu. I added a new menu and tried to add this to the language in the polylang settings on the menu tab.

The Problem is now, that the menu tab seems not to save anything. The other settings are working whithout any problem (I can change and save them). When I move into the menu tab the select input has not a language selected how it should. When I select a menu and save, I get onto the same page again witout any message and the select is empty again. Then I tried to change the menus of the other languages. The same result. Now no language has a menu defined and I cant save anything anymore. The checkboxes are also not working (I can change them, but if I save they reset and are empty). Its like the executed post is not executing any code or something like that.

I dont think that the multisite setting is causing this problem. The strange thing is that it worked until the menu was deleted.

Have you any idea what could cause this problem?
Thank you very much

http://wordpress.org/extend/plugins/polylang/