Arrrghh, so close yet so far....

I've just installed WoW for the PC on my Dell 8300 - 3Ghz, 1GB Ram. I have a Radeon 9800 card with the latest CAT 4.8 drivers. The problem: I can't get by the setup screen to run the game! The display driver is showing as a Radeon 9800 Pro and I can't get setup to hold any settings or autodetect. It gives me a "setup settings are still incorrect" error. I'm running Direct X 9.0b as per the manual. Anybody else run into this snafu with a Radeon 9800? Any suggestions?

Any help would be appreciated - after reading the posts about this game I can't wait to take her for a spin :p