sounds like there's an issue with firefox, then. either that, or something bad in your cache (such as old info from during fixes), or tech folks did some more work.
glad to hear you're back up and working
edit to add: just noticed that auctiva's listing serivce is on windows servers using ASP. Which would explain all the troubles with AOL, etc. Windows servers and ASP are known for not playing nice with non-microsoft browsers.