Activation : "Error: Unable to activate config for 'UNNAMED_INSTANCE_4' thread '4" (4217844)

 Activation on RAC unable to activate config due to "UNNAMED_INSTANCE_X' thread 'x'.

 sp_ctrl (<host>:<port>)> activate config <name>.config

   Error: Unable to activate config for 'UNNAMED_INSTANCE_4' thread '4'.

sp_ctrl (<host>:<port>)>

 Event_log:

 Notice   2011-02-18 14:33:38.740243 12833 4121745792 User command: oracle activate config <name>.config (from <hostname>)

Info     2011-02-18 14:33:38.745918 16266 4124837568 Activation launched, pid = 16266  (activating sid <SOURCE SID NAME>)

Notice   2011-02-18 14:33:38.983254 16266 4124837568 Activation: Oracle compatible parameter='11.2.0.0.0'.  (activating sid I<SOURCE SID NAME>) [module ocf]

Error    2011-02-18 14:33:39.604649 16266 4124837568 Activation: Failed to find hostname for instance: 'UNNAMED_INSTANCE_4' thread: '4'. ORA-01403: no data found.  (activating sid <SOURCE SID NAME>) [module ocf]

Error    2011-02-18 14:33:39.605048 16266 4124837568 Activation: Instance: 'UNNAMED_INSTANCE_4' thread: '4' might be down.  (activating sid<SOURCE SID NAME> [module ocf]

Error    2011-02-18 14:33:39.605642 16266 4124837568 Compile of "<name>.config" for sid o.<SOURCE SID NAME> failed: Error: Unable to activate config for 'UNNAMED_INSTANCE_4' thread '4'.