Itunes could not backup because an error occurred. (no error code)

I'm getting the "iTunes could not backup because an error occurred" with no error code. I've tried reading everything I could find for different fixes and nothing has worked.

Tried:
force backup by right click and select backup
Hard iPhone reset
kill iTunes and apple processes, restart iTunes
computer reboot
uninstall iTunes, re-install, reboot pc
delete photo cache from pc
delete all iPhone backups from pc
killed windows firewall

It's a Verizon iPhone 4 running ios 4.2.6. I almost never sync to the pc but wanted a backup before upgrading to the newest ios. I'm sure I could restore to the newest ios but I don't want to loose everything.

Any ideas? I'm wondering if it's a cydia app causing issues or something? Just searched that while typing and saw some possibilities. I'll still post this and report back with updates.

Thanks for any help.

Holy crap it worked. Found a post about XBMC (best media center ever) and a plugin for it causing someones backup not to work. I uninstalled XBMC, deleted any leftover files with ifile, and backup is working!