I can not get the following code to lock a record. What can can cause this failure? I've got multilocks on, and reprocess set to automatic for testing.

STORE recno() to gcreclist2
DO WHILE NOT RLOCK('myfile')
RLOCK(str(gcreclist2), 'myfile') &&& Lock clinical record
IF NOT RLOCK()
Wait window "Somebody else is working on this record"
ELSE
UNLOCK
ENDIF
ENDDO

thanks