Current status...

I downloaded BIAB patch build 1224 today and installed it.
I looked in the folder R:\bb\Drums\FolkPopSlow16thsBrushes
and found the text file FolkPopSlow16thsBrushes_60_style.txt
which had been missing from this folder prior to the patch.

I retested the problem I was having and the demo song now successfully generates the drum part with no errors.

I updated the thread title to reflect this testing.