You may need to install the propper drivers for your graphics card. If you are running an nvidia card, go to www.nvidia.com/drivers
Im not sure which other major card manufactorors make linix drivers.
If not, you may need more ram or swap space. Or if you have a bizzar hardware config you may need to make your own kernel.
Or the decoder for the video file you are trying to play is just in development and its not very good.
more info would be good about ur box