Movie Maker and annoying green bar

When I use Movie Maker to process an XVID file and it then calls DVD Maker,
the resulting DVD has a green bar across the lower-half of the screen. When I
use Movie Maker to convert the XVID file to WMV format, the resulting .WMV
file has the green bar, too.

When I launched DVD Maker manually and added the same XVID file myself, the
resulting content did not have the green bar. So this appears to be a problem
with XVID files in Movie Maker. The *menu* on the resulting DVD, however,
*does* have the green bar. Once the Play link is pressed and the content
begins to play, however, the green bar disappears. I'm not sure what is
causing this; could the menu creation feature that DVD Maker uses be hampered
by the same problem that is causing Movie Maker to generate the green bar?

Does anyone have a suggestion on how to:
a) get rid of the green bar from the files that Movie Maker generates?
b) get rid of the green bar from the menu that DVD Maker generates?