The LOCK MODE clause in the FILE-CONTROL paragraph of the Environment Division does not contain one of the words EXCLUSIVE,
AUTOMATIC, or MANUAL, or if it does, your COBOL system has failed to recognize the word, perhaps owing to a spelling mistake.
The LOCK MODE clause controls access to files shared between a number of users in a multi-user environment. Its form is determined
by the filetype with which it is used.
Resolution:
Correct the LOCK MODE clause.