iTunes won't backup iPad when syncing

I have iTunes 10.1 running on Mac OS 10.6.5 and my iPad 64GB WiFi+3G has been updated to iOS 4.2.1. I can't be able to complete a backup in iTunes after creating multiple folders. During the backup phase of an sync in iTunes, the backup phase seemed to stop progressing and the iPad kept rebooting until I pulled the plug. Just can't quite complete the sync process.After done a hard reboot, the