Either use e.g. Avicodec (see
Help to Help hereunder) or maybe you can find out by right-clicking on the video window, select "Properties" and then the Mpeg video-decoder.
(I have a strong feeling that the Mpeg decoder/filter you're using is causing your problem so that you must upgrade (or perhaps even downgrade) it or find another Mpeg decoder to replace it; by using "Search" you can find - if necessary - several links.)
PS:
Please also check you're using the latest version of BSPlayer (see
Help to Help)