Currently Being ModeratedMar 8, 2013 8:31 PM (in response to stevinator)
Go through the Apple-recommended trouble-shooting steps. At the least, run "repair database". My guess is that you'll end up having to delete your user prefs as well.
Details are on this Apple Aperture support page.
Currently Being ModeratedMar 15, 2013 12:36 PM (in response to stevinator)
The trouble-shooting steps were my first effort and made no difference at all.
I solved my own problem. It turns out my keychain was a mess. For reasons I don't understand it was HUGE. I repaired the keychain and now all is working as expected.