Holy hell.
What is going on with frame by frame. You cannot go more than a handful of frame before the application completely craps itself. Firstly, after 10 or so frames, the application will refuse to advance any more frames no matter how many times you hit the button. Secondly, the PLAY command starts to act really funny while attempting to play the content after initiating this glitch. Sometimes it will simply stop responding to PAUSE after initiating the glitch and hitting play. Then the media will end early (even when the file has more content on the timeline).
I get something like 10 or so frames before that button fails to do anything. The only thing that gets it working again is SEEKING on the media bar or hitting Play. You are likely able to FRAME BY FRAME again afterwards. Sometimes, however, it only allows another, single frame before freezing again.
It's really getting old. Please consider revisiting this code. It doesn't function as intended.