No errors shown after Compiled with errors message

I run Oracle 8.1.7 and try to create a package body with the script provided in the bottom of the message.  

Oracle says:

> Warning: Package Body created with compilation errors.

So I ask:

> show errors;

No errors.

A similar situation is in DBA Studio, where an "Invalid" indicator is shown against my package body, but the Error window is empty.

What's up with that ?

Do I need some patch or I simply missused some keywords ?

Best Regards,

Aleksey Burdakov

CREATE OR REPLACE  PACKAGE BODY "SYSADM"."S"        AS
     
	function ISN(str IN varchar2) return number IS
	BEGIN
		IF str IS NULL THEN
		    RETURN 1;
		ELSE
		    RETURN 0;
		END IF;
	END ISN;
  
	function ISN(n IN number) return number IS
	BEGIN
		IF n IS NULL THEN
		    RETURN 1;
		ELSE
		    RETURN 0; 
		END IF;
	END ISN;
 
	function ISN(d IN date) return number IS
	BEGIN
		IF d IS NULL THEN
		    RETURN 1;
		ELSE
		    RETURN 0;
		END IF;
	END ISN;

END S; / Received on Fri Sep 21 2001 - 12:07:39 CDT