Oracle Forms

hI
i have just put a datablock and a commad
and i have put a triger when boutton ptessed
and i ahve wrote
delete_record;
but the orcale could not delete the any record
and a message appears and says unable to save frm-40510 i looked in the help
and everything is corerct with me .even the button on the runtime form did not do it whenu commit the same error happens
is there any code to delete from a data block (tabular layout)
thanx