Switchover Error: ORA-16552: an error occurred when generating the CLIENT OPERATION table

 All,

 Configuration:

    11.1.0.7.4 - 4 node rac primary database replicating to a 11.1.0.7.4 - 3 node physical standby database.

    Test is switchover JCPRD (primary poduction) to JCUCN (physical standby)

     On the prodution node prdgrd1:

     . oraenv

    >JCPRD

    >export ORACLE_SID=JCPRD1

   >dgmgrl

   >connect sys/xxxxxxx@JCPRD

     >DGMGRL> switchover to 'JCUCN';
Performing switchover NOW, please wait...
Error: ORA-16552: an error occurred when generating the CLIENT OPERATION table

Error: ORA-00604: error occurred at recursive SQL level

Failed.
Unable to switchover, primary database is still "JCPRD"

 Any ideas....