Apple has pushed out an update to Aperture 3
that appears to fix a slew of little irritants users had been reporting, including upgrading from previous Aperture library versions, adding names and matches in Faces, adjustments using the Curve, Straighten and Retouching tools, and a number of other bug and stability fixes.
iMovie has also been bumped up to 8.0.6, primarily to give it better compatibility with Aperture. You should check your Software Update under your Apple menu, or go here
to grab the fixes. Detailed information on the changes is available at this Apple support page.