Sounds like your config file has been corrupted. Use the following post to locate your config file directory: viewtopic.php?t=2013
Then look for the files Meconfig.db and Meconfig.bak. With Multi-Edit(ME) not running you can try renaiming Meconfig.db to something else and then renaming Meconfig.bak to Meconfig.db. Then restart ME and see if that fixes the problem. If that does not work you will have to restore Meconfig.db to the factory defaults by deleting that file in the config directory and restarting ME.