Why does the video from my Samsung CL65 have black previews in iPhoto?

I have shot a ton of video on my Samsung CL65 camera. The previews are all black in iPhoto. I am using the latest version of iPhoto 8.1.1 (419) and the latest version of Mac OS X (10.6.2). Is there an update for Quicktime or something else that I can download to fix this? I love the HD video but it is really annoying to have black previews. I also frequently get an error when I try to edit the video in Quicktime and save it again (just trimming it).

Thanks!