Importing an mpg file

I used a DVD recorded to create a VOB file from an 8mm camcorder. I then
converted that file to an mpg file using VOB2MPG. When I import the mgp file
to WMM, I get audio only, no video. The video is there because I can play
the file in Windows Media Player and see. Why is there no video on my import
to WMM? Any hints? Thanks.