I found the solution to my problem. I moved all of my extension into the XTensions Disabled folder and restarted Quark. When I created a new project, Quark did not crash. So I tried restarting with just a few extension added at a time until Quark crashed again. The problem extension ended up being XPert PageSets.xnt (at the bottom of my extensions list, of course) from the XPert Tools collection. So if you have a similar problem, and are using XPert Tools, try removing the XPert PageSets.xnt extension from your XTensions folder.
Paul Trivilino