Appcrash error

Hello,
after making some small changes in my source, I cannot login anymore.
The client closes when I try to select a char or make a new one. I don't get a normal error message, just 'appcrash'.
I tried reverting the changes I've made, also checked if I accidentally changed some packets etc, nothign works. I've been trying for 3 days now but I can't fix it.
If I start a server from some clean repack, it works fine.
I'm also not sure where to look for the bug, I never got this 'appcrash' error before when just chaning the source.
Hope someone can help me, thanks.

Edit: Nvm, think I found it.