Face Time Problems

I have an iPad 2, model MC769LL, with a screen protector and leather smart cover, iOS 5.1.1. I keep calling my friend with Face Time, and after 10 seconds, it crashes. The way it crashed was strange though. The button used to end the call flashed red and brought me back to the contacts screen as if I had pressed it. I know I didn't press it, and this is really frustrating me! Does anybody know what is going on? If you can tell me anything, it would be much appreciated!

The Observer