The good news: Aperture now supports 64-bit operation. The bad news: Most of the plug-ins designed to work with Aperture don’t yet support 64-bit operation. This means, you have to switch Aperture to 32-bit mode in order to use plug-ins.
Fortunately, it’s easy to switch between 32-bit and 64-bit mode. Go to (File > Get Info.) With Aperture closed, check the “Open in 32-bit mode” box, then relaunch Aperture. All of your current Aperture plug-ins will be available to you.