Hi,
don´t know if you have already solved this issue by yourself, but just in case you haven´t I will tell you what caused this very problem for me and how I solved it:
I created my repaints in
Adobe Photoshop, saved them as .bmp but as you have said, the converter just stated "Stream- Lesefehler"
Tried several times, always the same result.
I then opened my saved .bmp (which came from Adobe Photoshop) in
Paint.net (can be downloaded for free) and saved it again as .bmp (overwriting the old version) and Voila! the converter tool did its magic and I now have my "Daysleeper" Nightbus driving around the streets of Spandau
For some reason although Photoshop saves the repaint as .bmp there obviously is a difference when saving it through Paint.net.
At least that was what caused this very error on my machine
Hope I could help
Cheers
Mark