I am far from being an expert, but doing 320x240, 5 bit planes at 50 fps is a 320 x 240 x 5 x 50 / ( 8 x 1024 ) = 2344KBps data stream. My guess is not all systems are able to do this.
Tahoe showed me a HAM video player that probably does some nasty stuff called HAMP.RUN, it would not display te dancing girls on my 3000 because of too slow disk access...
You could try to get a more efficient (differential?) schema and see if the CPU can create the new image fast enough or check out one of the existing movie file formats... Or just lower the image size...
