Apple have released Aperture v3.1.1. The download and description are available here
This update addresses overall stability and performance issues, and also includes specific fixes that:
The update is recommended for all users of Aperture 3.
- address compatibility with the iLife Media Browser
- improve reliability when upgrading existing Aperture libraries
- address issues with publishing photos to MobileMe, Facebook and Flickr
For detailed information on this update, please visit this website: http://support.apple.com/kb/TS2518