I have recently got a new imac and it has an sd card slot at the side. I have a hd camcorder with an 8gb sd card. When I put in in the slot it recognised it and when i double clicked it it came up with a load of files that have a black background with green lettering inside. When I open them i choose an application and it just says 'Unreadable Files'. I want to inport the video files to iMovie. Any idea what going on?