SQL & PL/SQL

I created the following procedure in sql*plus:

create or replace procedure p_test(tname in varchar2,user_name in varchar2)
AUTHID CURRENT_USER
is
pragma autonomous_transaction;
v_ddlstr varchar2(1000);
begin

v_ddlstr :=
'create or replace trigger trg_valid_' || tname || ' before insert on ' || tname ||'
declare
user_name varchar2(50);
object_name varchar2(50);
user_label number;
object_label number;

BEGIN

select userlabel into user_label from test.ULabel where username=' || user_name ||';

select objectlabel into object_label from test.OLabel where objectname=' || tname ||';

insert into temp values(object_label);

if user_label>object_label then
null;
else
RAISE_APPLICATION_ERROR(-20001,''you can not do that!'');
end if;
end;';
execute immediate v_ddlstr;
end;
/

and it succeed,
and in the test database ,i have create the following structure:

SQL> select * from table1;

A
----------
1
2


SQL> select * from ulabel;

USERNAME USERLABEL
-------------------- ----------
WXY 6
FEELING 3

SQL> select * from olabel;


OBJECTNAME OBJECTLABEL
-------------------- -----------
TABLE1 4
TABLE2 5

but when I execute the following statement:

sql>execute p_test('TABLE1','WXY')

some errors happen:

ORA-24344:success with compilation error
ORA-06512: in "TEST.P_TEST", line 31
ORA-06512: at line 1


then where is the mistake?thank in advance.