Could not do a physical-order read

We have a certain COM object that likes to fail with this message: Desc:[Informix][Informix ODBC Driver] [Informix]Could not do a physical-order read to fetch next row. sqlerrm(req_line) Src:Microsoft OLE DB Provider for ODBC Drivers Info: Message:'Unspecified error' The sql that it blows on looks like this: SELECT r.reqn_no, r.line_no, r.po_no, r.pur_line_no, r.condition_no, r.drop_ship,r.build_or_pur, lm.stocked, m.material_code FROM req_line r, pur_line p, loc_material lm, req_header rh, material m WHERE p.po_no = r.po_no and p.line_no = r.pur_line_no and rh.reqn_no = r.reqn_no and lm.location_id = rh.location_id and lm.material_id = r.material_id and r.material_id = m.material_id and p.po_no = 5526 ORDER by r.po_no, r.pur_line_no; It always executes correctly in dbaccess. I've tried using a dirty read connection in the com object to no avail. Any idea what "sqlerrm(req_line)" is trying to tell me or what else could be the problem? This is 9.4 TC2 sending to informix-list