Vista - Windows Media Player

When I play unpublished videos and imported videos on Windows Moviemaker II
everything is fine. Here's the problem: When I publish the video the file
when played in WMMII remains fine, but when I play it on WMP 11 the video is
essentially shortened in height by half. It looks pretty similar to a dwarf
compared to a human, the human is normally proportioned while the dwarf is
too short and too wide. The bottom half of the playscreen is taken up by a
green space. When I use effects on the video like 'grayscale' the green also
changes to gray, but I've tried downloading codecs to fix the problem and
nothing's worked. The only files I use to make the videos are .avi and I have
what I thought were appropriate codecs (DivX and Xvid). The entire video
comes out as wmv, but it doesn't come out properly.

It'd be great if someone would help me out with this. Support hasn't offered
much that was a help to me.