DROP TABLESPACE

Iam using Oracle 9i on winNT

When i fire these command i got these ERROR ?

Drop tablespace r_data8 including contents and datafiles
*
ERROR at line 1:
ORA-00060: deadlock detected while waiting for resource

I wonder if this could be aa trigger that is firing when your are dropping the table. If I was doing this I would drop all of the tables and indexes in that tablespace then drop the tablespace and see if that works. then I would do the following:
Drop tablespace r_data8 including contents;

If all of the tables and indexes are owner by the same user I would do a:
drop user uname cascade;