Help: Error pop-up keeps showing every time I reboot my Mac Mini

[EvilEvil]

Here's the dialogue box that pops up for me in Mountain Lion each time I reboot my Mac Mini.

The last time you opened Finder, it unexpectedly quit while reopening windows. Do you want to try to reopen its windows again?

I have googled this problem haven't found anything that helped in getting rid of it. Can anyone help?