Cascading Delete Referential integrity problem

Dear Friends, I have set cascading delete for master details tables, but whenever i delete the master it gives me the referential integrity error as follow, I have checked all the referential integrity in all chid table. i have this errors appeared: SQL error -692 : Key value for constraint (informix.project_key) isstill being referenced. has occurred. No changes made to database. DELETE FROM project WHERE sec_code = ? AND min_code = ? AND ri_code = ? AND proj_serial = ? AND proj_state = ? AND proj_title = ? ANDproj_key_words = ? AND pan_id = ? Your help is much appreciated. Syed. -- Syed Ibrahim Sapura Advanced Systems Sdn. Bhd, 18th Floor, Menara Tun Razak, Jalan Raja Laut, 50350 Kuala Lumpur, Malaysia Tel: (03) 295-3472, (03) 294-3000 Fax: (03) 294-6587, (03) 293-3154