Hmm, might be a problem with the Beta. You can rule out these two problems though:
-Your newest video driver at this
Link
-Your newest audio driver at this
Link
-Did you have these problems with the 1.0X patch?
-Do you get the same problem running in window mode?
-Can you launch a campaign scenario?
I'll be gone for the next few hours, hopefully someone else can follow up, or just bump your reply