Can anyone tell me why this procedure not works in sql2005 but works fine in Development server sql2000?

Can anyone tell me why this procedure not works in sql2005 but works fine in Development server sql2000?
if i commented the bottom is null than only it works fine in both Production and development database servers
select r.Description, b.build, s.serialno, bc.childserialno
From TbltcvRev r,
Tblsn s,
Tblsnbuild b,
TblsnbuildContent bc,
TblTCVariant tcv,
TblTypecode tc
where r.tcvrevid=b.tcvrevid and
r.tcvid=tcv.tcvid and
tc.tcid=tcv.tcid and
b.serialno *= bc.childserialno and
b.build *= bc.childbuild and
s.serialno='FC6084907811' and
b.serialno='FC6084907811' and
b.build = 1 and
(
Select ObsoleteDate
From TblSNBuild
Where SerialNo = bc.serialno and
Build = bc.build
) is null

Could you pls suggest me how to rewrite the new statement to use the proper
ANSI SQL OUTER JOIN syntax
I am a fresher guy for sql 2005/2000
thanks for your fast reply.

Frank, you forgot to drop the commas ...

Hi Frank,
I ran the query which you have suggested and got the error message :--
Msg 1016, Level 15, State 2, Line 38 Outer join operators cannot be specified in a query containing joined tables
select r.Description, b.build, s.serialno, bc.childserialnoFrom
TbltcvRev r,Tblsn s
,Tblsnbuild b
,TblsnbuildContent bc, TblTCVariant tcv
,TblTypecode tcwhere r.tcvrevid=b.tcvrevid and r
.tcvid=tcv.tcvid andtc
.tcid=tcv.tcid andb
.serialno *= bc.childserialno andb.build *= bc.childbuild and s
.serialno='FC6084907811' and b.serialno='FC6084907811' and b
.build = 1 and --(Select ObsoleteDate From TblSNBuild
--Where SerialNo = bc.serialno and Build = bc.build ) is null
(select obsoletedate FROM ...Tblsnbuild bLEFT JOIN TblsnbuildContent bc
ON b.serialno = bc.childserialno AND b.build = bc.childbuild)

The *= and =* ways of writing joins is no longer supported in SQL 2005. Not only in subqueries, but in any type of query. So make the same changes to your main query.