Oracle Database Discussions

Hi. I wont to enable table lock. I try this query/

ALTER TABLE owner.table_name ENABLE TABLE LOCK;

But I get

ALTER TABLE owner.table_name ENABLE TABLE LOCK

Error report -

ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired

00054. 00000 -  "resource busy and acquire with NOWAIT specified or timeout expired"

*Cause:    Interested resource is busy.

*Action:   Retry if necessary or increase timeout.

But There is not any other DML or DDL on this table.

The question is: How can I enable lock table?