Select statement works in 8.1.5 but does not work in 8.1.7 why???????

Question

I have written a select statement as part of cursor in a
Database Trigger, the following statement works fine in Oracle
8i ver 8.1.5.0 but the same statement returns error PLS-00103
(Parser related error) in Oracle 8i version 8.1.7.0!!!!!!
The error shown is
PLS-00103Encountered the symbol")" when expecting one of the
following:
from
The Sql statement in a Database Trigger is as follows
select opn_stk,iss_qty,rec_qty,ROWID
from mnth_bal
where to_date(lpad(to_char(month),2,'0')||to_char
(year),'mmyyyy') >= SYSDATE AND
REV_NO = :NEW.REV_NO AND
     ITEM_STOCK_ITEM_CD = :NEW.ITEM_CD and
unit_cd = :NEW.unit_cd and
store_cd = :new.store_cd
order by to_date(lpad(to_char(month),2,'0')
||to_char(year),'mmyyyy') ;
Can any one please tell me whats the problem ? In 8.1.5.0 the
same statement in the trigger runs absolutely fine &
compiles.Because of this problem the trigger is not compiling in
8.1.7.0
Would be grateful for any solutions given

Answer 1

Relating line numbers in compile errors to source code.
Oracle does not count blank lines in line numbers. Commenting
with "--" blank lines or deleting blank lines will make the line
counter more accurate.
Oracle counts comments delimited with /*...*/ as one line, no
matter how many lines are in the source code. Using only "--"
will make the line counter more accurate.
Oracle does not count lines before the PL/SQL block DECLARE when
compiling triggers. (CREATE ... TRIGGER....FOR EACH...WHEN(...))
parts of the syntax are not counted. The line in the source
code with the DECLARE of the trigger's PL/SQL block will be line
1.
Hint: Avoid uncertainty. Use "SHO ERR TRIGGER <trigger_name>"
when looking at compile problems.
Good Luck....