4.2 Installer hanging

Both threads stuck on:
0 7336 Main Thread Main Thread _KiFastSystemCallRet@0 Normal 0
0 > 1636 Worker Thread Win32 Thread _KiFastSystemCallRet@0 Normal 0

Win32 Worker Thread Call Stack:
> ntdll.dll!_KiFastSystemCallRet@0()
ntdll.dll!_ZwWaitForSingleObject@12() + 0xc bytes
ntdll.dll!_RtlpWaitOnCriticalSection@8() + 0xc8 bytes
ntdll.dll!_RtlEnterCriticalSection@4() - 0x4b84 bytes
ntdll.dll!_LdrpInitializeThread@4() + 0x49 bytes
ntdll.dll!__LdrpInitialize@8() + 0x7c bytes
ntdll.dll!_LdrInitializeThunk@8() + 0x10 bytes

Main Thread Call Stack:
> ntdll.dll!_KiFastSystemCallRet@0()
ntdll.dll!_ZwWaitForSingleObject@12() + 0xc bytes
kernel32.dll!_WaitForSingleObjectEx@12() + 0x84 bytes
kernel32.dll!_WaitForSingleObject@8() + 0x12 bytes
u3dapi10.dll!02709052()
[Frames below may be incorrect and/or missing, no symbols loaded for u3dapi10.dll]
u3dapi10.dll!027093c2()
u3dapi10.dll!026d9013()

u3dapi.dll is coming from CVSNT from TortoiseCVS. I'll try to remove from system and see if it makes any difference, but not until Monday.