I have another idea for you. I can remember reading obout such problems in the X-plane.org forums from other users. Although, I can't remember exactly what they have written about ... but! Google is our friend (in this case at least)! Try the following search, and it might help you:
If nothing else helps, I would recommend you to start a new thread (as NVidia tends to skip old/resolved ones!) AND/OR write to the linux-bugs email address (to make sure, they notice your question).
Andras / alpilotx