Problem solved.
I Copied all Movie Files from iPhoto to Documents and then reconnected the Files with the Project.
Seems like, with the new update it is impossible to import Video files from iPhoto, and even thou it effects your current Work so much, that it leads to crash by launching.
But first you have to Stop Rendering, and Erase Rendering Files.
I used the sec. he tries to load up the project to stop rendering and delete rendering.
To reconnect the Video files, you got to be in Final Cut X and you got to have the Event and the Project available.
Otherwise you can't reconnect the files, so don't hide them.
If the Video files are gone, like in my case, you just simply go to HOME, Movies, Final Cut X, Event, Original Data to check. There it was, were I recognized that the Video files are only KB sized instead of MB size, like they used to be.
Well, it worked for me.
Thanks to Tom for trying to Help me.
Please, Keep on Helping
Best
The Gerrit