Facetime for Mac gives me an error that says "quit unexpectedly".

Why does it do this? I try to make a call from my Ipad2 to my Mac Min using Facetime, and the app on my Mini shuts down and gives me an error message every time. It seems like Facetime is running fine on my Ipad2, but it's the desktop version that is faulty. I've reloaded the app 3 times and they obviously haven't found the bug. Apple support is anything but...anyone know how to fix? The rest of the error message reads like this:

Process: FaceTime [54134]

Path: /Applications/FaceTime.app/Contents/MacOS/FaceTime

Identifier: com.apple.FaceTime

Version: 1.0.2 (166)

Build Info: FT_Monaco-1660000~1

App Item ID: 414307850

App External ID: 3531181

Code Type: X86-64 (Native)

Parent Process: launchd [85]

I bought the Ipad2 so I could facetime with my family while on the road, and ironically it's the desktop version that is failing me. Thanks in advance to anyone who can help me!