Kinda screwed with Patch 1.02 at the moment.
Tried to log in at 8pm and got a message saying a patch was available - which it installed.
Then you try to run the damn program again and it complains that "Diabalo III is already running"
Looks like the new client won't work until Blizzard complete updating their servers
Frustratingly, Hell just got a hell of a lot stronger...