I cannot drop oracle schema

 Hi to all,
I try to drop one oracle schema and I receive the following error:

SQL> drop user tstuser cascade;
drop user tstuser cascade
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-21700: object does not exist or is marked for delete

In alert.log I found the following information:

Warning: drop_queue_table: No evaluation for the queue table: TSTUSER.BNA_MQ

Then I try to find the above object but of course I didn't found.

SQL> select owner,object_name,status from dba_objects where owner='TSTUSER' and object_name='BNA_MQ';

no rows selected