Okay, well I found a workaround, so if anyone else has the “line 217” error message when it comes to Encore 5.1 and slideshows, here is a link to an earlier discussion about possible causes. Thread is lengthy but informative:
https://forums.adobe.com/message/1813137#1813137
To summarize my particular fix, there were 2 things I did which may have finally made Encore happy.
First, via Photoshop, I resized all 197 images to a linear resolution of 72ppi and set the width dimensions to 720 pixels (for a standard 4:3 display). Earlier tests on shorter slideshows had no problem with much bigger files (rez was 300), but I’m guessing that 197 big files spread across 2 slideshows were too much for Encore to handle. Secondly, as suggested by the above thread, I originally checked “set length to audio duration” to adjust the overall length, and then unchecked that option and extended the duration of a single image to be about a second longer, so the visuals were “longer” than the accompanying audio file. I finally was successful in burning a video DVD of the slideshows (had to make a couple of pan and zoom changes on 4 images to remove playback glitches).
Not sure which one of these adjustments made the difference. But for what it’s worth, this may work for anyone else that’s encountered the “line 217” error and doesn’t want to use After Effects or Premiere to get it resolved.