ORA-06550 error while executing Dynamic Sql

Question

EXECUTE IMMEDIATE 'BEGIN :out := ' || lv_formula || '; END;' using out RESULT ;
here lv_formula:= ((capcost * rate / 100) + (ob + (ob * interestrate / 100)))
lv_formula is varchar2(360);
and capcost,rate,ob & interestrate are my column names . Here I m declaring variables same as these columns and datatype is number.
I am not getting any compilation error. syntax is correct
while executing this sql i m getting ora-06550.
can any one help me for resolving this error.
Thanks In Advance
hoping for more respose

Answer 1

Thanks Billy for your response,
but i still didn't get my desired solution so i am pasting my whole plsql code here. so that u can get better picture.
/* Formatted on 2010/11/22 15:23 (Formatter Plus v4.8.5) */
PROCEDURE xb (
l_refno IN VARCHAR2,
l_billtyp IN VARCHAR2,
infor IN VARCHAR2,
aresult OUT NUMBER
IS
--A NUMBER:=10; B NUMBER :=5;
lv_formula VARCHAR2 (270); --:=(A+B)*2+5;
l_agtmnt VARCHAR2 (18);
l_type VARCHAR2 (2);
RESULT NUMBER;
refno afxbrmst.refno%TYPE;
billtyp afxbrmst.billtyp%TYPE;
ob afxbrmst.ob%TYPE;-- := 45283;
status afxbrmst.status%TYPE -- := 0;
dueamt afxbrmst.dueamt%TYPE -- := 0;
duedate afxbrmst.duedate%TYPE;
frequency afxbrmst.frequency%TYPE;
lastrevrate afxbrmst.lastrevrate%TYPE -- := 0;
penaltyamt afxbrmst.penaltyamt%TYPE -- := 0;
accounted afxbrmst.accounted%TYPE;
lastbillraised afxbrmst.lastbillraised%TYPE;
noofstaff afxbrmst.noofstaff%TYPE;
items afxbrmst.items%TYPE;
area afxbrmst.area%TYPE;
LENGTH afxbrmst.LENGTH%TYPE -- := 0;
interest afxbrmst.interest%TYPE -- := 0;
capcost NUMBER; afxbrmst.capcost%TYPE; :=1;
-- := 1509432;
periodfrom afxbrrate.periodfrom%TYPE;
periodto afxbrrate.preiodto%TYPE;
rcsrate afxbrrate.rcsrate%TYPE -- := 0;
length_area afxbrrate.length_area%TYPE;
rate afxbrrate.rate%TYPE --:= 0;
-- :=3;
erate afxbrrate.erate%TYPE -- := 0;
feamount afxbrrate.feamount%TYPE -- := 0;
interestrate afxbrrate.interestrate%TYPE -- := 0;
-- :=12;
fiamount afxbrrate.fiamount%TYPE --:= 0;
penaltyrate afxbrrate.penaltyrate%TYPE -- := 0;
l_ob afxbrmst_test.ob%TYPE -- := 0;
l_capcost afxbrmst.capcost%TYPE -- := 0;
raise_application_trigger EXCEPTION;
inti INTEGER;
BEGIN
--break;
lv_formula :=
TO_NUMBER ((capcost * rate / 100) + (ob + (ob * interestrate / 100)));
--infor;
l_agtmnt := l_refno;
l_type := l_billtyp;
BEGIN
SELECT a.refno, a.billtyp, a.ob, a.status, a.dueamt, a.duedate,
a.frequency, a.lastrevrate, a.penaltyamt, a.accounted,
a.lastbillraised, a.noofstaff, a.items, a.area, a.LENGTH,
a.interest, a.capcost
INTO refno, billtyp, ob, status, dueamt, duedate,
frequency, lastrevrate, penaltyamt, accounted,
lastbillraised, noofstaff, items, area, LENGTH,
interest, capcost
FROM afxbrmst_test a
WHERE billtyp = l_type AND refno = l_agtmnt;
EXCEPTION
WHEN NO_DATA_FOUND
THEN
NULL;
END;
BEGIN
SELECT b.periodfrom, b.preiodto, b.rcsrate, b.length_area, b.rate,
b.erate, b.feamount, b.interestrate, b.fiamount, b.penaltyrate
INTO periodfrom, periodto, rcsrate, length_area, rate,
erate, feamount, interestrate, fiamount, penaltyrate
FROM afxbrrate b
WHERE billtype = l_type;
EXCEPTION
WHEN NO_DATA_FOUND
THEN
NULL;
END;
EXECUTE IMMEDIATE 'BEGIN :out := ' || lv_formula || '; END;'
USING OUT RESULT; --USING OUT RESULT;
aresult := RESULT;
END;
-- Procedure
here i m passing the parameter through my form builder and calling this procedure.
can you tell me where i am making wrong
Thanks again