I'm getting an error message about s_Generation.

You can get this message in a replicated database when you run an append query that contains the asterisk (*) in the Field row in the design grid.  The asterisk selects all the fields from one of the underlying tables. To avoid this problem, remove the asterisk from the design grid, and then add each field from the table's field list to the design grid by double-clicking the title bar of the field list.