Try deleting your Aperture preference file and re-launching. I had problems with both iPhoto and Aperture with the last round of updates. Both kept crashing; when I tried to export an image in iPhoto is kept trying to send it to Shutterfly and crashed iPhoto.
Make sure Aperture is not running. Go to Home/Library/Preferences/com.apple.aperture.plist and delete it. Restart Aperture and it will create a new preference file and should stop the crashes.
If that doesn't work, I have read of people having to uninstall Aperture, install Aperture 3.1 and then update it to Aperture 3.4. Deleting Aperture will not delete your libraries, but MAKE SURE YOU HAVE BACKUPS OF EVERYTHING JUST IN CASE!
Make sure Aperture is not running. Go to Home/Library/Preferences/com.apple.aperture.plist and delete it. Restart Aperture and it will create a new preference file and should stop the crashes.
If that doesn't work, I have read of people having to uninstall Aperture, install Aperture 3.1 and then update it to Aperture 3.4. Deleting Aperture will not delete your libraries, but MAKE SURE YOU HAVE BACKUPS OF EVERYTHING JUST IN CASE!