Target database name does not match recovery catalog

I have unregister and register the database for several time now. After register, I ran full backup, it will run fine. But all the subsequent backup, it will fail with the following error.

connected to target database: INT (DBID=2959146586)

 

Starting backup at 12-APR-13

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of backup command at 04/12/2013 02:00:15

RMAN-03014: implicit resync of recovery catalog failed

RMAN-06004: ORACLE error from recovery catalog database: RMAN-20004: target database name does not match name in recovery catalog

 

Recovery Manager complete.

I went to the recovery catalog and queried:

SQL> select * from rman.db;

    DB_KEY      DB_ID CURR_DBINC_KEY