I created three read-only materialized view last week. One of the materialized view - mviewA -- is based on another materialized view- mviewB. I encounted the following error on mviewB:

ORA-12012: error on auto execute of job 261
ORA-12008: error in snapshot refresh path
ORA-01631: max # extents (121) reached in table SYS.SUMDELTA$
ORA-00604: error occurred at recursive SQL level 3
ORA-01631: max # extents (121) reached in table SYS.SUMDELTA$
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 604
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 661
ORA-06512: at "SYS.DBMS_IREFRESH", line 577
ORA-06512: at "SYS.DBMS_REFRESH", line 211
ORA-06512: at line 1

If I select count(*) from mviewB, I have 0 records in it.
refresh method: force
Database is 8.1.6.

Any help will be greatly appreciated.