Modified Wow.exe with most common crash in recent beta build fixed: DownloadCreator: TOM_RUS (mangos founder)
Lets hope blizzard won't miss NULL pointer checks next time.
Original topic: here and also here(ru).
Blue posts about it: here
This fix fixes the stability issues in the 15640 MoP Beta build.
As far as I know the issue with the bad stability and missing pointer is fixed in the 15650 build. Just patch up your client. If you see all realms red, in means that you need to patch your wow client to the latest build, just run launcher.exe. If you get any error, just read any of my other blog posts on how to fix that.
The problem should have been fixed in Build 15650.