Strange behaviour in Nero Vision Express 6-- no preview image

I loaded an AVI file into Nero Vision and wanted to
add some chapters.

The small image of the first frame was visible in the
add window.

Attempting to engage the playback screen to add
chapters at desired points failed.


I got sound from this playback attempt but no image
in the preview window. So everything seems to be working
except the playback video. What's the solution?


I can burn the thing as is but I'd prefer a chapter
break... I even know where to put it at 46:03 mins.
If there's a way to do it manually that's fine too.

Previous practices with this chaptering feature
seemed to work ok. So I don't know why this
particular avi obtained from download does not
display the image but only plays the audio.