If none of that works it could be iTunes itself and
First I would Check For Updates in iTunes
If that does not work:
I would uninstall and reinstall iTunes.
Removing iTunes, QuickTime, and other software components for Windows Vista:
http://support.apple.com/kb/HT1923
Removing iTunes, QuickTime, and other software components for Windows XP:
support.apple.com/kb/HT1925?viewlocale=en_US
Removing iTunes for Mac OS X:
support.apple.com/kb/HT1224