I would go ahead and remove AOL through the control panel. The message is probably just warning about AIM or some component that loads resident in RAM on boot up (launcher program).
What I have found about AOL is that if you use it and any of their AV, Spam protection, or other protections is that unless you are logged into AOL you are NOT protected. I have seen many machine compromised by this, left on with a high speed connection and then whacked with spyware, virus, and pop ups, just because someone left the machine on and not looged into AOL.