I've read a lot of topics about this issue. But none of them really describes my problem.
So one the solutions to solve the errors that are occuring if you combinate facebookSDK with JSON is to rename the JSON classes that are causing a conflict.
SO that is exactly what I did. I have renamed all the classes that where causing the errors (not only the filenames ;).
So now when I run my app Xcode sais: no complications, BUT I get thread 1 sigabrt.
The whole Xcode message:
Couldn't register blabla.blabla with the bootstrap server. Error: unknown error code. This generally means that another instance of this process was already running or is hung in the debugger.Current language: auto; currently objective-c (gdb)