I had odd crashes like this occur with a theme when I was trying to use rainmeter-0.9 (the last xlabel-hookable version, AFAIK). I don't know *why* it crashed, but if you look in the application event log you may see "Application error" events. If you look at the details, at least some of them will identify the offending module - rainmeter in my case. I ended up making xlabel meters instead and dropping rainmeter. No more crashes. =)