Motion JPEG

I have an avi file and in gspot it is a MJPG including Huffman tables file. When I run the movie, it is just a pink and green screen but the movie doesn’t play. Do I need to decode it or what and where can I get the proper codec in order to get the movie to work? And what player do I need in order to get a MJPG/XVID movie to work. Thanks in advance