Can you find where Zero K lobby is stored? if you found it, then there's text file called "ZeroKLobbyErrors.txt". This store error for ZKL if ZKL crash/stopped working.
If its error with Spring.exe then you must follow instruction by Skasi , if its error with ZKLobby, then you must find the "ZeroKLobbyErrors.txt".
The file contain detailed information on what cause ZKLobby crash/stop working.