Err.7 = End of game..?

I've a guildie who has a pretty serious problem..

From what I've been told they were in the second to last mission and got an Error 7. When he got back into game he was unable to access the mission and couldn't go back to redo the quest where he got the mission objectives from. Seems kind of like his quest log deleated the next primary quest (or mission, he wasn't too sure) before it's completion and now he cannot go back and get it...any suggestions?

Which campaign was he playing? Second to last mission for sure?
Could you please find out the name of the outpost, mission, or link quest?