Why can't i get Facetime to work

I've recently bought a Macbook pro which already had Facetime pre-installed (version 1.0.3) but for some reason it will not work!! That is, I can't even log in under my Apple ID.

The thing falls over when I sign in - it produces and message to say that I can't sign in and I need to check my network connections.

I have checked and double check that i am using the correct Apple ID username and password with the apple web site (manage your Apple ID) and my wife uses Facetime via her iPhone which works OK.

So I'm assuming that our internet connection is fine, since my wife is able to use the iPhone Facetime at home and I'm trying to use the same network, and that I am entering my Apple ID correctly, but why won't it work!!

I see that the App Store is selling Facetime 1.0.2 - has this something to do with it?

Where am I going wrong?

Can anyone offer any suggestions?

Thanks