Messages "glitch"?

Hey Guys! I'm new to Macs, although I LOVE my new MacBook Pro!

I just upgraded to ML from Snow Leopard, and I love the messages app. One problem I'm seeing is the screen sharing portion of it. If I try to share my screen or ask someone to share their screen, I get the following message:

This computer does not support audio chat (or something very similar). I don't have anyone on I can test it with right now or I'd send you the exact message.

I currently own a 13" MacBook Pro, Early 2011
Processor 2.3 GHz Intel Core i5
Memory 8 GB 1333 MHz DDR3
Software OS X 10.8.1 (12B19)

Is anyone else experiencing such a thing? Otherwise, the upgrade went flawlessly, in 20 mins I was running Mountain Lion, and it's just as fast as Snow Leopard.

Thanks!