As far as I know "publish" is correct - the name is different in german, so I hope it'S the same. This sound like one of WMMs many surprises, like it won't work correcly with the footage.
There should be different settings when you try to publish to your computer (concerning size and quality of the video), does it do this on every one? You could try if it looks correct in a different output setting.
I do not know this particular error. If you don't get better help here, I suggest you look (or ask) here
http://www.windowsmoviemakers.net/Forums/Maybe, the problem is known there. :gift: