Most likely one of OE's .dbx files is corrupt. Do a search of the harddrive for "*.dbx* (without the quotes, with the asterisk and dot). You may find more than one folder containing .dbx files but generally the one with the "inbox.dbx" that was modified most recently (right click on the file, go to Properties, check "Date Modified") is the folder which OE is actually using.
Start by renaming the inbox.dbx file to inbox.old, try to open OE. If that doesn't work, rename the folders.dbx file to folders.old and try OE again.
If that doesn't work, the next most likely suspect is spyware, specifically Hotbar, which has been known to mess up OE. If you haven't already, download, install, immediately update
and then run Spybot
. Read the help files to familiarize yourself with how they work. I recommend you use them both since each tends to find things the other misses. Let them clean up any spyware found. See if removing spyware helps out with the OE problem.
To turn off AIM starting up when OE does, try OE's Tools>Options>General tab, uncheck "Automatically logon to....etc.," click OK and see if that fixes the problem.