Recently updated to aperture 3, now my camera isn't recognized when plugged in.

Upgraded from Aperture 2 to 3 using the app store. My camera is a Canon Rebel XTI. When I plug it in the CF light blinks and the LCD becomes inactive as if it is communicating with the computer but nothing happens on the mac. Aperture doesn't launch and nothing mounts. My computer is a 13" Macbook Pro. Everything worked fine prior to upgrading Aperture. Tried several USB cables and that's not the problem. Restarting didn't help either.