Did you also update Aperture? Aperture 3.1.1 had a bug, that might cause crashes, when applying adjustments using MacOS X lion.
You should at least upgrade to
for Aperture to run reliably with Lion, if you cannot (or don't want to) upgrade to the most recent Aperture version 3.4.2.
But before upgrading Aperture, be sure to keep a backup of your current Aperture library and to repair/rebuild the Aperture library using the Aperture Library First Aid Tools (Aperture 3 User Manual: Repairing and Rebuilding Your Aperture Library). The Aperture upgrade will upgrade your Aperture library as well, so you will not be able to open it any longer with the older Aperture version. And the upgrade may fail, if the library has problems, like inconsistencies that can be caused by crashes.
Regards
Léonie