The code below is exactly what I used to prepare the SQL cursor:

=cursorsetprop('Tables', lcTableSource)
=cursorsetprop('UpdateNameList', lcUpdateNameList)
=cursorsetprop('KeyFieldList', lcTableKeyField)
=cursorsetprop('UpdatableFieldList', lcUpdatableFieldList)
=cursorsetprop('SendUpdates', .T.)
=cursorsetprop('UpdateType', 1)
=cursorsetprop('Buffering', lnTableBuffering)

The field lcTableKeyField always contains the PK for that table, each table only has one PK, so I don't think the issue is with the PK list. The lcUpdateNameList is a field containing all of the field names, i.e. so I can update any field in the table.

Thanks in advance.