PROCEDURE proc(msg IN NUMBER, details IN VARCHAR2 DEFAULT NULL)
IS
   PRAGMA AUTONOMOUS_TRANSACTION;
   moduleName VARCHAR2(48);
   actionName VARCHAR2(32);
   currentTimestamp LogTable.EventTimestamp%TYPE;
   osUser     VARCHAR2(30 BYTE);
BEGIN
DBMS_APPLICATION_INFO.READ_MODULE(module_name => moduleName, action_name => actionName);
INSERT /*+ APPEND */
INTO EpnpaLog 
VALUES
(logLevel  /* package-level variable of type NUMBER */
,CURRENT_TIMESTAMP
,moduleName 
,actionName 
,msg        
,details    
,sys_context('USERENV', 'OS_USER')
);
END proc;

DECLARE
var VARCHAR2(4001);
BEGIN
var := 'text long for 4001 characters [COLOR=red]...[/COLOR]';
CREATE TABLE t (col VARCHAR2(4000));
INSERT INTO t VALUES var;
END;

SQL> CREATE TABLE t (col VARCHAR2(4000));

Table created.

SQL> declare var VARCHAR2(4001) := rpad('X',4001,'X');
  2  begin
  3    INSERT INTO t VALUES (var);
  4  end;
  5  /
declare var VARCHAR2(4001) := rpad('X',4001,'X');
*
ERROR at line 1:
ORA-01461: can bind a LONG value only for insert into a LONG column
ORA-06512: at line 3

SQL> @v

Version Oracle : 10.2.0.4.0