Dreaded 3073 Non-updatable Query Problem

I recently inherited an MS Access application. To bring it up to company standards, the data needed to be rehosted in DB2. The screens remain in MS Access. To accomplish this with no/minimal code change, I followed these steps:

1) For each access table, I created a DB2 table with the same structure. (table name and field names changed based on company standard)
2) Created a link table in access for each DB2 table
3) removed each Access table and replaced with a query (based on link table) with same name. The query maps field names us AS clause.

The reports and screens paint fine but any update operation results in a 3073 error. 'Operation must use an updateable query'. There are no joins or aggregates in the query.

Any suggetions?

thanks
Howard