Cool -- being sarcastic
I spent the afternoon rebuilding the app from a new project, copy pasting the code... Now I opened the older one once again, tried to run it just...just to try once again, knowing it would crash cause I haven't change a word it already crashed every other time I tried earlier this morning, and.... surprise: runs again. No errors.
-.-'' Solution to my question then? No idea. Still thinking it was some cache problem that eventually got solved through out the day but not while I was trying to solve it.
If anybody has had similar experiences or has some further idea, feel free to add something, always good to be prepared for next time something like this happens.