My friend and I have been having trouble with multiplayer in Borderlands 2. Whenever I join his game his says that the xbox is unable to read the disc, sends me to the main menu and him to the dashboard. He has the downloadable version off of Xbox LIVE and I have the disc version. I also have most DLCs (except for most of the skin packs). I was trying to join as Krieg the Psycho which we've done flawlessly before.
Also, when we tried having him join my game it said on his screen that I was in a DLC he didn't have when I was in Sanctuary. This all started before the recent compatibility pack update' I think after the recent game update.