Can't alter database flashback on, ORA-38777 on cluster

$ srvctl stop database -d db -o immediate
$ srvctl start database -d db -o mount
$ env | grep SID
ORACLE_SID=db1
$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.2.0 - Production on Wed Mar 29 17:32:12 2006

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.


Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> alter database flashback on
2 ;
alter database flashback on
*
ERROR at line 1:
ORA-38777: database must not be started in any other instance.


SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options


-------------So resolve this problem----------------
Start on node


$ srvctl stop database -d db -o immediate
$ srvctl start instance -d db -i db1 -o mount
$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.2.0 - Production on Wed Mar 29 17:34:09 2006

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.


Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> alter database flashback on;

Database altered.

SQL> alter database open
2 ;

Database altered.