iCal Converts my appointments into blank New Event

Hi guys,

First this problem happens only since I upgraded to Mountain Lion (version 0) and only on my Macbook pro.

So whenever I create a new event in iCal, after I've filled all the infos (name, location, hour, ...) whenever iCal synchronizes it changes my event into a blank new event.

This does NOT happen when I create a new event on my iPhone (iOS 6).

Can you please help me ?

Hope you can help me with this because that's a major problem in my daily job.

Thanks a lot for your answers