Gather statistics on fixed objects after upgrading to 10g

Recently RMAN backup failed after 10g upgrade. On digging in error logs, the following was discovered:

SQL> select count(*) from v$rman_status ;
select count(*) from v$rman_status
*
ERROR at line 1:
ORA-01652: unable to extend temp segment by 640 in tablespace TEMP

Incorrect statistics on FIXED objects

Bad execution plan needed much sort-space.
Multiple waitevents on 'direct path write temp'.

Fix: As per Metalink Note 357765.1

SQL> exec dbms_stats.gather_fixed_objects_stats;