You should be able to ping directly from your pc, with it connected through the router (either directly or wirelessly). Assuming you're using XP, use Start | All Programs | Accessories | Command prompt. Then type
ping
www.sportsclubhost.com
and press Enter.
You can do the same from within the Netgear DG834G, by logging into it using your browser, and clicking Diagnostics from the left hand side.
Having said all that, when IE asks you to check spelling and network connection, it's usually because it can't create a network connection to the web server. Assuming that you can surf other sites fine (including presumably this one), then I would assume that your router's OK, and that your own network and PC setup are fine. I'd give the ISP support a ring, as they're best placed to help you out.