I have this issue whenever I try to zone from one area to another. Looooong load time in which I can read all three codices regardless of their length, get up, fix something to drink/eat, come back and I'm just getting to the black screen which also lasts into forever. And finally BOOM!!! CTD.
I thought it may be my CPU (which is barely inside minimums to play, but didn't have issues prior to Trespasser and the latest patch), but now beginning to think it's a larger issue.
I also have random disconnects from the Dragon Age Servers, so using the Golden Nug is an iffy proposition at best.
Repairing the game, clearing my cache, and rebooting my PC didn't help.
OP do you have a warrior with the Lunge and Slash or Line in the Sand skills? Those caused issues for me with crashing during combat as well, but disabling them in tactics worked.