Disabling all AddOns scares me, but I'll try it
The only problem is that I don't know which quests cause this strange behavior, so when I play for about 2 or 3 hours while questing a lot and it does not happen, what does it tell me? Almost nothing, because it could just be that there was no quest which triggers this error. So, to be accurate, I have to play 2 chars. 1 char with all AddOns and then, when this error happens, another char with only Carbonite enabled, to see if it happens at this quest again... Hmmm, that means a lot of questing to do today. But when it helps, I'll do it, but it will eventually take till monday, because my son is having a birthday-party tomorrow, so theres a lot of work to do for parents *g* But I will definitely test it.
I'll report back a.s.a.p.