Thought I'd share this information with you.
I did not have this problem at first, but I doublechecked and i did find somebody else with this problem, she was using IE7, running windows XP professional SP3(machine is updated every friday through WSUS, so it was up to date), and running Acrobat 5(an office machine, acrobat was not the free(reader) version but the full package including distiller, etc.), when visiting this site it brought up some awkward error, and i noticed that acrobat was running when i looked in computer management, the fix did not require any other updates other then running CCleaner while temporarily disabling the network connection. After CCleaner(wich basicly searches for useless registry entries and browser certificates/cookies) and a cold restart(useless probably, but just to be sure) I could navigate to here again(as exactly to witch entry it was, on any users computer CCleaner finds tons of "C", so i did not take the effort to isolate this..
chris is right on with AVG, another free quality package is antivir(Keep in mind once you do get a warning, and let it pass through the AV package, you are lost forever, so installing a second one just to run a full scan and de-install it might be a good idea)
-The only thing that could cause the frontpage to even look at adobe would be the link to the arena manual, so whatever Kris would be fixing, it is not unique to this site-