the error today seems to have vanished --
I added sentences to set variables to nothing and erase arrays
also, the source workbook is now open in a macro-disabled instance of excel, so there are less things potentially causing the problem.

with arrays I had some trouble in the past and finally settled for this approach which at least didn't cause errors.

in any case -- I'll keep in mind your comments and apply them wherever possible.

thanks for your time!