seacue,
Since the WinXP Viewer by default fits the pixs to the size of your screen, you might not be seeing it. Try within the WinXP Viewer clicking CTRL+A, which will make the picture show its actual size.
Let me know if you can see this line then?
Take Care,
Richard
P.S. That line you are seeing could be the reflection off the wall of the projectors light source.