How to execute a stored proc with output params

Question

I have a SP that I created with 2 input varchar2s and 1 output varchar2. I developed it using PL/SQL Developer where it compiles and tests OK.
When I try to run it using exec it fails with:
exec validstate2('300', '5')
BEGIN validstate2('300', '5'); END;
ERROR at line 1:
ORA-06550: line 1, column 7:
PLS-00306: wrong number or types of arguments in call to 'VALIDSTATE2'
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored
If I try to add a set of quotes for an empty string for the output it fails as well.
What do I need to do to get this to run? How do I handle that output parameter?
Rick Price

Answer 1

Here's the SP code, getcountry2 and get state are both functions that seem to work just fine.
create or replace procedure ValidState2(mesgid IN varchar2, vcondition IN varchar2, valid OUT varchar2) is
vvalid varchar2(20);
v_temp varchar2(3);
begin
v_temp := getcountry2(mesgid, vcondition);
IF v_temp = 'US' then
vvalid := getstate(mesgid);
valid := vvalid;
else valid := 'Not US';
end if;
EXCEPTION
when NO_DATA_FOUND THEN valid := 'No Data Found';
end ValidState2;