No guarantees it will work for you but here's a
copy of a message from a user who solved the issue:

===
Fixing the Green Bar Problem in Windows Movie Maker
Fixing the Green Bar Problem in Windows Movie Maker, Bernie Zimmermann

When I tried to follow the directions, I was unable to find XVid on my
computer. So I googled XVid and then went to ( I think) the 2nd entry to
download XVid. After I downloaded it, I was able to follow the directions
from bernzilla and when I published a video - Voila!! no green bar!!!!
===


Good luck.