Cant watch Channel Ondemand via Channel4 website

Hello Can anyone help me? I am trying (and failing) to watch Channel 4 Catch Up television programmes On Demand.

My mates computer works but mine doesnt. I have Windows XP, Service Pack 3, IE8, Firefox, Newest versions of Adobe Flash, Shockwave etc and Avast! Virus Scanner. My ISP (Student Provider Keycom formerly known as Digital Village) is British and runs at approx 2mb per second peak.

When I click the programmes to watch, it just says "Loading Content" and the disc keeps spinning attempting to load but nothing happens it just keeps on doing this for ever. It should activate and play an advert and then the required television programme.

I have logged the error to Channel4.com and am currently awaiting response from them. I would really gladly appreciate it if any majorgeeks could have an idea whats going wrong?

Cheers for helping