Okay, here's what some other guy did:
1
Error: AppName: ut3.exe AppVer: 0.0.0.0 ModName: kernel32.dll
ModVer: 5.1.2600.3119 Offset: 00012a5b
When this appeared, he "updated the last drives of motherboard and video card" - I think he means he updated the drivers.
Then he got this one:
2
Error: AppName: ut3.exe AppVer: 0.0.0.0 ModName: ut3.exe
ModVer: 0.0.0.0 Offset: 00d5c3c2
After that, he followed the following instructions to change the UTEngine.ini.
Edit the UTEngine.ini which can be found in My Documents\MyGames\Unreal Tournament 3\UTGame\Config.
[Engine.ISVHacks]
DisableATITextureFilterOptimizationChecks=False
bInitializeShadersOnDemand=True
PumpWindowMessagesWhenRenderThreadStalled=True
...and then...
[SystemSettings]
OnlyStreamInTextures=True
If it doesn't help, try googling the exact error message, you'd be surprised how many other people have had the same problem.
Also, you said "ModVer: %.1.2600.3119 Offset: 00012a5b", I'm pretty sure you meant "ModVer:
5.1.2600.3119 Offset: 00012a5b".