did you also remove your MobileMe account from the Web-Panel in the Aperture preferences? I found that after signing in to Mobile Me this was added automatically in Aperture again, after I had removed it previously.
If your account shows there, remove it; also uncheck: automatically check for published albums.
I am turning off, deselecting/deleting MobileMe and there's a great feature that makes it much easier to do so [in terms of helping one's fear of losing photos!] - when you hit the delete button [ - ] it asks whether you want to lst import the photos into Aperture - I am sure they are dups but just in case they're not, I'm importing them - I can then delete them in Aperture - I'm moving from MobileMe anyway so it makes sense to do this ==
I do think it odd tho that the "autocheck" deselection wasn't enough in MobileMe but it was in Flickr = which doesn't constantly update [eyt] --- thanks for the help, I think it's working now.