Are you trying to use the web based e-mail or the acutal software. If you are using the client there could easily be a block at the router and or firewall preventing access. I know my company does that at all the remote offices since they don't want the bandwidth wasted. Or if its web based can you ping it or do a tracert, to the aol web mail page, does it find the site (I don't know the URL)?
I'm using the web-based email. I don't actually run AOL from work. I can get to the aol.com site and also to the screen name sign-in page but after I try to log on I get that message. I had been using it with no problems until a few days ago.