If your game is crashing on start (as mine was), check for conflicting programs that may be having an impact. Most people that have had this issue were also running the Curse client, including me. Closing this worked for me. If it doesn't work for you, there is likely some other program conflicting. Try closing all unnecessary programs that are running on your computer and trying again. If this doesn't work, do a fresh install using the most recent BETA build, and try again with Curse/applications closed.
Good luck.