'Next frame' feature ruins video and audio

[exsequar]

I just upgraded to 1.0.3 and immediately found a big problem with the 'Next frame' shortcut, which I use a lot. When I do it now, the video skips forward 10 or 20 seconds, gets completely pixellated and loses audio entirely. Sometimes I can get it back to normal by clicking around, but usually everything's totally screwy until I restart the file. Is this something I can fix? Should I revert back to the last version?

I'm using a newish MacBook Pro with Snow Leopard. Thanks for any advice!