ORA-12054 when trying to create an MV

Question

10gR2
I'm trying to create an MV, but is failing with the mentioned error. I've tried to search for the reason(s), but cannot seem to find it. Can somebody help? Thanks.
create materialized view MV_POC
build immediate
refresh on commit
enable query rewrite
as
SELECT
SRBU.SRV_REQ_ID as SRID,
ORGNZ.NAME as DIVISION ,
SRVRQ.CREATED as OPENED,
SRVRQ.SR_SUBTYPE_CD as SOURCE,
USR.LOGIN as OWNER
FROM SIEBEL.S_PARTY PRTY,
SIEBEL.S_ORG_EXT ORGNZ,
SIEBEL.S_SRV_REQ_BU SRBU,
SIEBEL.S_BU BU,
SIEBEL.S_SRV_REQ SRVRQ,
SIEBEL.S_USER USR
WHERE SRVRQ.ROW_ID = SRBU.SRV_REQ_ID (+)
AND
SRVRQ.OWNER_EMP_ID = USR.PAR_ROW_ID (+)
AND
( PRTY.ROW_ID = ORGNZ.PAR_ROW_ID AND PRTY.ROW_ID = BU.PAR_ROW_ID AND SRBU.BU_ID = PRTY.ROW_ID)
AND (ORGNZ.INT_ORG_FLG = 'Y' AND BU.BU_FLG = 'Y')
AND (ORGNZ.PAR_BU_ID = (SELECT ROW_ID FROM SIEBEL.S_ORG_EXT WHERE NAME = 'State of Washington')))

Answer 1

From the documentation you failed to search
ORA-12054 cannot set the ON COMMIT refresh attribute for the materialized view
Cause: The materialized view did not satisfy conditions for refresh at commit time.
Action: Specify only valid options.
Those valid conditions are likely documented, and likely they have to do with the numerous outer joins, maybe on primary key columns, may be not.
Most views must be 'key-preserved' to be updatable.
Sybrand Bakker
Senior Oracle DBA