Are you playing the game off the DVD or hard drive (if available)?
I had a couple lockups (fortunately less than a couple minutes from saving) playing the US Xbox version, after it had been on all day, so I suspect heat may have been an issue.
It appears non-US Xbox versions will not be updated until the next patch. Larian is still making changes (game balancing, engine optimization and bug fixes) to the main game as they are working on the
add-on, so the beta testing procedures may get combined to save time and resources (MS also has limits on the size and number of patches that can be released for Xbox games).
Other than confirming certain fixes would be in the next patch, though, there has been nothing official mentioned.