What should I put in my forum admin general configuration for Domain Name, or is that really the problem? My site does not have a www in it and when someone posts in the forum and I get notified by e-mail and click on the link, I get server not found and the link includes www in it. But when I remove the www in the address bar in internet explorer and click enter, the page is still not found.
What I have now in the domain name in forum admin is www.martingy2k.no-ip.com. Should I change this?

I just have web-forums.co.uk/nuke without the www in mine and I don't have any probs

Thanks dar63!! You just fixed a major problem and saved me a lot of time. This instructions for this part of setup for the forum was lacking in detail and so of course I guessed wrong.