I'm running 311.2 on Windows 7 32Bit with no problems.
Disable UAC in windows 7 (open msconfig, tools tab, highlight change UAC settings, click launch, slide the slider to bottom notch, click ok.
Install VAGCOM as usual, no need to run in any compatibilty mode.
Plug USB VAGCOM cable in to PC/Laptop and let the windows update find the driver and install automatically.
Once driver installed goto device manager, expand the 'ports tree' and double click the new installed device....I think its called 'USB Serial Port'.........click port settings tab, click advanced and change the COM Port Number to either COM 1, 2, 3 or 4 (choose one that is not 'in use').
Now open VAGCOM and click options, select COM Port to same one you have just used in Device Manager. Click save.
VAGCOM should work fine now!!