How To Check And Insert New Data Using Stock Procedure

i've a problem in using store procedure. My code is to get postcode id when i pass a postcode. First it will check the postcode that i pass if already exist it will get postcode id but if not it will insert new postcode and get a new postcode id created then pass into ASP system. When i try run this stock procedure i got error as below :-

SQL> exec INSERT_PCODE_GMDS
BEGIN INSERT_PCODE_GMDS; END;

*
ERROR at line 1:
ORA-06550: line 1, column 7:
PLS-00306: wrong number or types of arguments in call to 'INSERT_PCODE_GMDS'
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored

(
Postcode1 IN varchar2,
citiID IN Number,
county_ID IN number,
city_name IN varchar2,
sub_cityID IN number,
pcode OUT number
)
[code].......

in ASP to pass and get back the values i used code as below. but i think the problems occurs in my stock procedure

set cmd=Server.CreateObject("ADODB.Command")
cmd.ActiveConnection = OBJdbConnection
cmd.CommandText="INSERT_PCODE_GMDS"
cmd.CommandType= 4
cmd.Parameters.append cmd.CreateParameter("@poskod",adVarChar,adParamInput,5,poskod)
[code].......