iChat does not recognise webcam

[Chalkster]

when using iChat it says in preferences under the video tab that there is no camera attached to the computer. It has as you know the built in web cam, this does work with Photo Booth and some other chat clients.

Any ideas how to get it working with iChat?

 

[Chalkster]

If anyone having the same problem although looking at response it doesn't look like it I\ve found that if I close iChat once system running and then reopen iChat video is usually there.