ORA-01555 caused by SQL statement below (SCN: 0x09ad.86a4562a):
Sat Jan 21 08:39:45 2012
SELECT (NVL(MAX(BLOCK_ID + BLOCKS ),0) * :b1 ) / 1024    
FROM DBA_EXTENTS  WHERE TABLESPACE_NAME = :b2  AND FILE_ID = :b3

undo_management                      string      MANUAL
undo_retention                       integer     900
undo_suppress_errors                 boolean     FALSE
undo_tablespace                      string

Step 1. create undo tablespace

Step 2. 
ALTER SYSTEM SET UNDO_TABLESPACE=UNDOTBS;
ALTER SYSTEM SET UNDO_RETENTION=900;
ALTER SYSTEM SET UNDO_SUPPRESS_ERRORS=FALSE;
ALTER SYSTEM SET UNDO_MANAGEMENT=AUTO SCOPE=SPFILE;

Step 3:
Restart the database.

SQL> show parameter rollback

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
fast_start_parallel_rollback         string      LOW
max_rollback_segments                integer     122
rollback_segments                    string
transactions_per_rollback_segment    integer     5
SQL>
SQL> show parameter transaction

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
transaction_auditing                 boolean     TRUE
transactions                         integer     610
transactions_per_rollback_segment    integer     5