Can't connect to 1 web site

There is one web site I can't connect to using its name. If I use its IP
address I can get there but can't move around from page to page. I get the
message "IE cannot display the web page". I have friends who can connect to
the web page using its name. As far as I know there is only one web site so
affected, I seem to be able to connect everywhere else.

Operating System : XP Home SP3 auto-updated
Browser: IE and/or Firefox
Internet : Cable 2MB - computer connected to modem by cable
TCP/IP settings: both IP address and DNS sever address obtained automatically
ISP: Virgin (UK)
web site required: avonscouts.org.uk
IP address of required web site: 91.103.218.30

I have contacted Virgin who say they think it is my computer problem.

I feel there must be something lurking in the nether regions of my machine,
can anybody help me to find out where and what it is?

Plmurray