ZwiebelZ,
Sorry for the non-verbosiness, let me make myself a little more clear.
Starting with November 13th CVS, the parameter of the function CastSecondsToHM (from aMule) has been changed from sint32 to uint64. The problem is with the routine wxString::Format (from wx), which was having problems with handling those uint64 parameters, but I think this issue has already been fixed.
So please, try a more recent version of wx libraries and report your results.
Cheers!