After a quick
Google search there appear to be two fixes.
1. On Microsoft Windows XP, not sure if it's the same on Vista (post in comment if you have any idea, thanks!). In Internet Explorer, go up to Tools > Internet Options. Then go to the last tab, Advanced, and scroll down to the Security section. It is the fifth box down and make sure "Check for server certificate revocation (requires restart)" is unchecked. Then access the iTunes Store as usual and hopefully it will fix the iTunes 9808 error. Best of Luck!
2. The other was DNS related so I would go with option 1.