I just updated my iPhone 3G to 2.1 jailbroken. I synced everything, didn't restore any backups in iTunes, then I installed all of my old apps I had before. When I try to download some YouTube vids with MxTube I would get this error. I already uninstalled it and reinstalled it a couple of times and I'd still get the error. I have no idea what to do now, I'm pretty sure I don't have to restore it again, cause this was a completely fresh install.