Originally Posted by jeaton2012

For those of you having issues with Finder even after you've fixed xpchelper, I've managed to track down the problem relating to copy/paste/empty trash. Just download this application I wrote and click disable kext cache to fix the problem and restore kext cache if you're having problems with the fix

EDIT: Oh yeah, and don't forget to reboot after you've fixed it!
EDIT EDIT: If you have high CPU usage because of xpchelper crashes after you've fixed the com.apple.xpchelper.cache. Just do: sudo mv /System/Library/CoreServices/ReportCrash /System/Library/CoreServices/ReportCrash.backup