ORA-00106: cannot startup/shutdown database when connected to a dispatcher

Problem Description
We are running a multi-threaded server and are trying to shutdown the database using Oracle Enterprise Manager. But it fails through below message

ORA-00106:
cannot startup/shutdown database when connected to a dispatcher

In simplest, ORA-00106 means following according to oracle documentation.

ORA-00106:
cannot startup/shutdown database when connected to a dispatcher
Cause: An attempt was made to startup/shutdown database when connected to a shared server via a dispatcher.
Action: Re-connect as user INTERNAL without going through the dispatcher. For most cases, this can be done by connect to INTERNAL without specifying a network connect string.

Cause of the Problem
The problem happened because you are trying to shutdown the database while connected to a shared server process. Because you cannot startup or shutdown a database while connected to a shared server process via a dispatcher. To shutdown or startup a database you must connect via a dedicated server process.

Solution of the Problem


In order to startup/shutdown a database, you must connect via a dedicated server process and not a shared process.
If you are connecting to database server through TNS entry then add the following entry to your tnsnames.ora file in the address_list section:

(SERVER=DEDICATED)

Example of a TNS entry that establish a dedicated connection:

 service_name= 
      (DESCRIPTION = 
          (ADDRESS_LIST = 
             (ADDRESS = 
              (PROTOCOL = PROTOCOL_NAME) 
                (Host = server_name) 
                (Port = port_number) 
             ) 
          ) 
         (CONNECT_DATA = 
             (SID = sid_name) 
             (SERVER=DEDICATED) 
         ) 
       ) 

Another solution is login to the server and issue startup/shutdown from that computer by connecting as sysdba without any TNS entry.
Related Documents
http://arjudba.blogspot.com/2008/05/startup-fails-with-oracle-error-ora.html
http://arjudba.blogspot.com/2008/09/database-startup-fails-with-ora-27302.html
http://arjudba.blogspot.com/2008/07/database-startup-fails-with-error-ora.html
http://arjudba.blogspot.com/2008/08/startup-fails-with-ora-01261-parameter.html
http://arjudba.blogspot.com/2008/09/database-startup-fails-with-ora-00444.html
http://arjudba.blogspot.com/2008/05/database-startup-fails-with-errors-ora.html
http://arjudba.blogspot.com/2009/05/ora-27100-shared-memory-realm-already.html