Apple Sync Notifier.exe - System error

I updated to iTunes 9.2, after that I receive the following message when I restart or boot my comp. "Apple Sync Notifier.exe - System error. The program can't start because CoreFoundation.dll is missing from your computer. Try reinstall the program to fix this problem" I did that a few times still the same thing. When I tried to install OS4 it took 3 hours to back up my iphone then the OS4 were downloaded fine. After about 4 hours I get a message "Back-Up failed" and I am back at version 3.1. Any advice?