iTunes could not copy "" to the iPhone "" because an unknown error occorred (-50).

This is a very annoying problem. I've followed everything by the books and cannot figure it out.

I'm getting the warning iTunes could not copy "[Song Name]" to the iPhone "[Phone Name]" because an unknown error occorred (-50) and don't know what to do. I've followed Apple's guildline - http://support.apple.com/kb/ts1539 - of uninstalling, reinstalling, reregistering .dll files, restoring the phone, updating the phone, making sure the "Convert higher bit rate songs to 128 kbps AAC" option was not checked, etc. Does any body have any idea what the issue is here? I just did all of this after updating iTunes to 10.4 and my iPhone 4 to 4.3.4 and am running Windows XP. I've had the issue for about 3 weeks - it occured both after reformatting my PC's hard drive and installing iTunes 10.3 (I know others had issues with 10.3). ANY help would be amazing. Thank you!