UGH, the bane of my existence. I had similar problems Nvidia Kernel issues and NWN for the better part of two years or so on my laptop. What was infinitely frustrating was that every time I thought I had a fix, and did what I was supposed to, it would work for a time before cropping up again.
The fact that it's only on your DM client confuses me a little, though!
Some of the core Nvidia kernal issues come from NWN being an old game that has unusually slow refresh rates. Some Nvidia cards will believe that the game is actually crashing as it's rendering and loading. There's a way to broaden the accepted refreshing rates, but I forget how and I'm probably not using the right terminology. :/ Someone else might have an idea from this. I think it has to do with underclocking, maybe?
The other things have to do with power related issues. The most common fix is what Bahamut suggested, but if that doesn't work there's a few other things. If you're using a laptop, try unplugging its power cord while playing and see if that changes anything (Or inversely, having your power cord plugged in but your battery removed). Also, when I had this problem on a laptop (I still don't know if you do or don't have one), I disabled my Nvidia card and just used its onboard card instead. This isn't preferable, but it'll run.
Another thing I was told to do was to try running NWN in compatibility mode.