This may or may not help.
Under Properties -> Compatibility, I have NWN set to run under Windows XP (Service Pack 3) Compatibility Mode. I have also checked Disable Visual Themes and Disable Desktop Composition.
There is also an option somewhere called Data Execution Protection which used to prevent all non-Microsoft programs from running in XP (I think it's off by default in Windows 7). You might check to see if for some reason you have that turned on. I would tell you were to find it, but, ironically, Windows 7 is screwing up for me when I look in Control Panel (Explorer keeps crashing).
