ORA-01940 error - very stange - please urgent help

Hi

I created a user named SSI_ACX with some objects (tables, views, ...). Later on I connected with SYS user and tried:
DROP USER SSI_ACX CASCADE
but I got the error:
ORA-01940: cannot drop a user that is currently connected.
Of course first thing was to check this, but there is no connection with this user; SELECT * FROM v$session WHERE username='SSI_ACX' returns no rows.
Next thing I tried was to connect with this user to the database, but I got ORA-01017: invalid username/password; logon denied!!!!
I can see the user (if I connect to the database with another user) and even it's objects. I even tried ALTER USER SSI_ACX IDENTIFIED BY ... and it worked, but there is no way I can connect or drop the user.
Does anyone know what is the problem here? I shoul really drop this user very quickly...

For info, I am using Oracle 10.2.

tried restarting the database?

I saw some info about a bug out there related to this on version 9.2. I would think it's fixed for 10.2 but who knows. Here it is:


First check if there is no duplicate of SQLPLUS_PRODUCT_PROFILE and/or DUAL.

SQL> SELECT owner, object_id, object_type, object_name, status
FROM dba_objects
WHERE object_name = 'SQLPLUS_PRODUCT_PROFILE';


SQL> SELECT owner, object_id, object_type, object_name, status
FROM dba_objects
WHERE object_name = 'DUAL';

If no duplicate row then this is Bug#3799696.