SD card fails to import — generates endless "Loading Assets" routine.

I seem to have a dodgy 8GB SD card, although it functions in the camera (Canon SX30), and I can manually transfer the photos into Aperture 3.2.1. Attempting to use the Import functions in Aperture result in zero activity apart from at lower left of the Aperture window, where the spinning paddlewheel endlessly spins while Aperture is equally endlessly "Loading Assets".

On the first occasion this happened, after a day or two elapsed the message popped up telling me "not to be a naughty boy and properly eject the media" (although I rarely lapse in that regard). After ackowledging same, Aperture appeared to have resumed normal operations.

At the second probing attempt to import from this card,the malfunction resumed, and I have reformatted the card in the camera.

My quetion is: "Is the any way I can break the loop?"

As I view the situation, force quitting is not required because both iMac and Aperture are otherwise working fine.