iMovie does not open anymore - Console: -10699

I used iMovie a lot in the past days (Mac Mini Late 2012 - Mac OS X 10.10) but now if I press the icon in the dock it just does nothing. With spotlight search the same and opening it from the Finder makes no change either. I looked at the Console and the error was the following:

In some other forum it said to deinstall and install the AdobeFlash but that did not work. Also I rebooted my Mac which made no change.

Has anyone got an idea how to fix it without reinstalling (if possible)?

Thanks in advance!