Windows Movie Maker does not Publish all of video using .WMV files

The video runs nicely until it hits a certain clip and then it goes black. I
used .WMV files for the entire clip. I read the file type compatibility
articles. According to them, this should publish. I have constantly had
issues with Windows Movie Maker Vista, but these sort of problems do not
occur with Windows Movie Maker XP. I have always used the same file types
while publishing. I know my movie maker is not publishing all my files,
because it only takes 3 minutes to publish on Vista opposed to an hour with
XP. What should i do?