FaceTime does not connect, iChat video does not work, Skype video does not work (LION)

Question

Hi everyone,
I am using OS X 10.7.3 2011 Macbook Pro 2.2 Ghz Intel Core I7 8GG 1333MHz DDR3 RAM 500GB HD.
What happens when I try to call someone in FaceTime: Webcam light is on and I see myself on my screen. It rings and after a while it says "X is not available for FaceTime (or similar).
In iChat I can text chat, but video calls do not work. In Skype, I can do audio talking, but when I try to use my video, it fails to connect.
This seems to indicate to me that there is a system-wide, rather than user or program-specific problem, in which my system cannot connect to others when using my webcam.
Can anyone offer any guidance on this matter? I am pretty tech savvy. On my home network I have tried port forwarding/opening and all that, without luck. I am worried that maybe I could have made a mistake in terminal or something some time ago, but I don't go in there very often and it is usually for very specific things.
Any help would be greatly appreciated. I am moving away for four months, and I really need this to work so that I can chat with my lovely girlfriend. Please see the notes below prior to commenting.
Cheers
Notes:
Internet is working fine. I use three different network, one of which is wired and works fine.
I have tried to create new users, still no luck
Webcam works fine in PhotoBooth
I am logged into FaceTime properly (this is simple, right?)
Reinstalling OS X to fix this problem is not an option
I have tried FaceTime with several people with several devices (e.g., iPad, iMac, iPhone)
FaceTime on my iPhone works with other people on same network

Answer 1

Please read this whole message before doing anything.
This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.
The purpose of this exercise is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login. Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode and log in to the account with the problem. The instructions provided by Apple are as follows:
Be sure your Mac is shut down.
Press the power button.
Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone, but not before the tone.
Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).
Note: If FileVault is enabled under Mac OS X 10.7 or later, you can’t boot in safe mode.
Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.
Test while in safe mode. Same problem(s)?
After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of the test.