The family didn’t work, got error (didn’t copy as it went away when I removed the F###).
No error other than your own. ASSO can only be used between individuals. GEDCOM definition says: The association pointer only associates INDIvidual records to INDIvidual records.
and An indicator to link friends, neighbours, relatives, or associates of an individual
If you are adding ASSO to an event (rather than directly to the individual kiwitrees has the facility to add two ASSOciates on the same edit screen.
Otherwise you have the option to use the “copy” feature after entering the first ASSO.