Hi everyone, there is a very simple Direct.Draw error fix that (I think) will fix most all issues. I am running Parallels 6 (Build 6.0.11994) with Windows 7, everything updated. Mac OS 10.6 updated.
By default, Parallels sets the video card to 32 megs, and importantly, no 3d acceleration. You must change this to at least 256 megs of memory for the video card, and turn on 3d acceleration. This can only be done after you shut down the virtual machine. The settings are found in hardware/video settings.
Inquisit won't run unless you have 3d acceleration enabled, and enough memory to run it.
Hope this helps.