If your AOL suddenly stops connection or never would connect on OS X, here is a possible solution:

Do you connect through a Linksys Router? If so, go to their site and get the firmware upgrade for it. However, in order to install it, you will need to run MacTFTP client, available HERE.

Stuffit expander will probably expand the linksys upgrade file, but you may have to manually unstuff the mactftp client.

Start the client , type in your router's address, just like you would in your browser to get to the administration page, type in your router password, then select the "code.bin" file in the folder containing the firmware upgrade, and hit Send.

The process starts out slowly but speeds up as it goes. Then restart the router, restart the mac, and see if you can get to the web. If not, access the router's administration page, and click the Setup tab. I had to change the WAN setup pulldown menu from obtain an IP automatically to PPOE. When you select PPoE, you get fields to type in your user name and password to your ISP account. type those in and hit Apply. You should now be up and running, and be ready to try AOL again.

Thanks very much to the people on MacFixit, and to Barry Diamond specifically for this tip.
See this page for more info. Be sure to scroll down the page or you'll miss the solution which is contained in the comments.