What are you playing back from? Is the media on a hard drive or on a card? K and L work. Not J. Playback can be very sluggish if you’re playing off a card. There is no jog wheel or shuttle, but you can scrub the playhead, sort of.
This isn’t normal, intraframe compressed media. Most of the frames aren’t complete information. I-frames are complete, and subsequent frames read off it so playing forward is relatively simple. Playing backwards though is a problem. The first frame you encounter when you play backwards is probably not an I-frame so playback would have to skip backwards to find that I-frame before it could play the frame you want to see. That would be kind of a mess.
All the best,
Tom
Class on Demand DVDs “Complete Training for FCP7,” “Basic Training for FCS” and “Final Cut Express Made Easy”
Author: “Final Cut Pro 5 Editing Essentials” and “Final Cut Express 4 Editing Workshop”