I recently was working with a compound report and one of the reports had ON fieldname SUBFOOT NOSPLIT. It worked fine running just that report, but when the compound report ran, I was getting errors. Turned out I needed to put them on separate lines:
ON fieldname NOSPLIT
ON fieldname SUBFOOT
" footer "

The errors were not helpful so I thought I would share this in case anyone else runs into it.

Actually, I had a blank footer (" ") and the first error I got was about having no text for the subfooter.

Was the original syntax coded by hand or did App Studio create it? Also, how did you figure out that's the problem?

Actually I had the same problem and did the same thing. I did not think to post this. my bad.

Thanks

BabakNYC - the code pre-dates my start with the company but I suspect it was originally generated by DevStudio. I was adding a couple of reports but working in AppStudio text editor.
To figure it out I searched FocalPoint, looked at the technical documentation and did lots of trial-and-error.