Hi Oracle Gurus,
I am getting this error when i am trying to chage the datetype from varchar2 to Nvarchar2.
Can anyone help me out in this...its very urgent....

SQL> ALTER TABLE S_ACCNTRT_LOAD MODIFY (COMMENTS NVARCHAR2(250));
ALTER TABLE S_ACCNTRT_LOAD MODIFY (COMMENTS NVARCHAR2(250))
*
ERROR at line 1:
ORA-25207: enqueue failed, queue . is disabled from enqueueing


Thanks in advance
Mahesh Kumar BK