Hi. Just wanted to share my event viewer entry for the same problem under Win7/64:
Faulting application name: avidemux2.exe, version: 2.5.6.0, time stamp: 0x4efc4cf6
Faulting module name: msvcrt.dll, version: 7.0.7601.17744, time stamp: 0x4eeaf722
Exception code: 0xc0000005
Fault offset: 0x0000996a
Faulting process id: 0x1b50
Faulting application start time: 0x01cd6dcc554753f6
Faulting application path: C:\Program Files (x86)\Avidemux 2.5\avidemux2.exe
Faulting module path: C:\Windows\syswow64\msvcrt.dll
Report Id: 95a94a8d-d9bf-11e1-90d9-005056c00008
Regards.