I've been using a Logitech G5/G9 for... a while now and had no issues with NWN at all, so it might be a pretty specific thing. I know this might be a -really- odd thing to ask, but have you tried lowering the "Polling Rate" in the Logitech SetPoint (...I think that's what it's called) thingy? I don't know why but I seem to remember someone mentioning it.
the only time I've crashed so far was due to a player who unshifted (don't confuse this with the topic crash as this is a different type of crash, and if anyone knows a fix for shifter crashes please do tell!)
Should've been fixed with the 1.69 patch, hum. Might be something else, I guess! D: