I cant see why being on AOL would stop it doing as its done before.
Have you tried it on another pc to make sure that the button hasnt packed up ?
Have you tried using the CD if it came with one ?
Trust is getting to be a big name in PC peripherals now so maybe they have a forum for trust products if you do a search and see if anyone has the same problem with AOL or possibly a solution.
I assume that clicking on the back arrow on the AOL browser takes it back a page, if not then its something in the AOL setup.
If it does that ok then its got to be a problem with the mouse or its settings I would think, but withoyt being at the pc I cant imagine what the problem would be.