Hi Dirtman,
You're right - the problem was at my end. It required quite a bit of detective work to sort out.
I'm running XP with SP3 and Trend Micro antivirus which deactivates the Windows firewall and uses its own. Java is installed.
I was getting the "404" error.
After checking firewall, security and antivirus settings to no avail, I turned to the modem. I disabled DHCP and enabled NAT. I then went to the Internet Protocal settings in Windows and assigned both IP and DNS server addresses instead of obtaining them automatically. Still no luck.
As a last resort I changed the DNS server address to that of another ISP, and lo and behold it worked! Bloody finicky things these computers!
Thanks for your suggestions,
Kevin