Hi,
here is a simple tool for all AOL users, it does and usually works but not that 100% perfect, you will need to launch this using your AOL browser, meaning you should be inside the AOL software and not using IE or Netscape, the only thing it does is it automatically refresh itself to simulate activity on AOL and will keep the dreaded IDLE timer from getting active, try it and please leave a note so that we will know how effective it is.
http://www.tekpinoy.org/noidle