Oracle - Problema con un procedimiento

Hola a todos.
tngo problemas con este procedimiento.

create or replace procedure calc is

tab_name varchar2;
col_id number;
col_size_v number;
tam number;
row_size number;

cursor tab_names is select table_name from user_tables;

begin
open tab_names
loop
fetch tab_names into tab_name;
EXIT WHEN tab_names%NOTFOUND;
row_size=0;

for column_id2 in select column_id from cols where table_name=:tab_name
loop
select decode(data_type,'NUMBER',trunc((data_precision+1)/2)+1,data_length) as size_col
from user_tab_columns
where column_id=:column_id2 and table_name=:tab_name

IF size_col >= 250 THEN
tam := size_col + 3;
ELSE
tam := size_col + 1;
end IF;

row_size= row_size + tam;
end loop;
IF DEBUG THEN
dbms_output.put(' Tabla: '|| tab_name ||' Tamaño: '|| row_size ||' bytes ')
dbms_output.new_line;
END IF;

END LOOP;
CLOSE tab_names;
end;

cuando trato de crearlo, me marca este error
Warning: PROCEDURE created with compilation errors.
estoy utilizando Toad 8.0...... y oracle 9i . no se que esta mal ni como hacer para saber en que linea fue el error.

por favor alguien puede ayudarme tks.

create or replace procedure calc is
tab_name varchar2(40);
col_id number;
col_size_v number;
tam number;
row_size number;
size_col number;
cursor tab_names is select table_name from user_tables;
begin
dbms_output.enable(1000000000);
open tab_names;
loop
fetch tab_names into tab_name;
EXIT WHEN tab_names%NOTFOUND;
row_size:=0;
for cursor in (select column_id column_id2 from cols
where table_name=tab_name)
loop
select decode(data_type,'NUMBER',trunc((data_precision+1)/2)+1,data_length)
into size_col
from user_tab_columns
where column_id=cursor.column_id2 and table_name=tab_name;
IF size_col >= 250 THEN
tam := size_col + 3;
ELSE
tam := size_col + 1;
end IF;
row_size:= row_size + tam;
end loop;
dbms_output.put_line(' Tabla: '|| tab_name ||' Tamaño: '|| row_size ||' bytes ');
END LOOP;
CLOSE tab_names;
end;
/