I'm not trying to claim credit for this fix because I think I can't say that I'm the first one to come up with it. I had a problem with my HTC Thunderbolt camera loading then as soon as I switched to the front facing camera it forced closed. This is what I did to fix the issue.
Step 1: Go to Setting>Applications>Manage Applications>Camera
Step 2: Press Force Stop & Clear Data
That's it. Try the camera again and it should work. This problem can be the cause of your video chat not working.
Step 1: Go to Setting>Applications>Manage Applications>Camera
Step 2: Press Force Stop & Clear Data
That's it. Try the camera again and it should work. This problem can be the cause of your video chat not working.