I get ORA-01401 error, my friend does not

create table test1 ( x char(2));

create or replace PROCEDURE STATISTIC_test(X_T char) AS

BEGIN
INSERT INTO TEST1( X ) VALUES ( X_T );
END STATISTIC_test;

ORA-01401: inserted value too large for column
ORA-06512: at "ITVUSER.STATISTIC_TEST", line 4
ORA-06512: at line 6
Process exited.

You did not show how you called the procedure. But I'd be willing to bet on the basis of the ORA-1401 error message that the parameter you passed to the procedure was more than two characters long. Your table has a column, X, defined to hold a maximum of two characters. You either need to redesign your table to hold more than two characters, or only pass in two characters (or less) in the procedure's parameter.