Insert, But Not Update Or Delete

Humm, been going over this and can't figure where I am going wrong.
Linked SQL server table.
SQL permissions are correct (cause every thing works via QA using pass through security).
Form with a CBO to select Item1, once selected list box populates with Items tied to it.
Select item from list box click button to break the tie between the two.
3 tables, Item1 Table, Item2 table and cross reference table that ties them together. The Break Tie basically (should) remove the entry from the cross ref. table. Form allows me to insert a new tie (same premis as break only allows you to select items not tied currently) and will insert a row into the cross ref. table. But it will not allow me to delete, or as a backup plan I tried to zero out the FK values. Delete says not allowed (bad permissions, table read only, etc.) and Update says must use an updatable query.
NOW the queries I have used are basically DELETE FROM CrossRef Where PK = nnnn OR UPDATE CrossRef SET FK1 = 0, FK2 = 0 WHERE PK = nnnn
I mean it does not get any easier than that.
So what am I missing on this? Why won't it let me delete/update that stupid table?