Setup 10G to access external DLL on windows2000 - ORA-06520: PL/SQL: Error loading external library

Neither I nor the C coder that i am working with has attempted to setup an external procedure before so the help is greatly appreciated. Does the following error mean that oracle configuration is correct and now there is an issue with the DLL itself?

Unfortunately the C coder compiled on WinXP Pro and the 10G is on Win2000, any idea if this will work?

Error on line 0
begin
Call_Scaling_Factor (1,'NSLS','AP_OWNER','AP_OWNER', 'AP_CONS'); end;

ORA-06520: PL/SQL: Error loading external library
ORA-06522: Unable to load DLL
ORA-06512: at "AP_OWNER.CALL_SCALING_FACTOR", line 1
ORA-06512: at line 2

Here is how i setup and called the extern proc in the db

CREATE OR REPLACE LIBRARY libscf AS
'C:\oracle\product\10.1.0\Db_1\BIN\ScalingFactorDLL.dll';

CREATE OR REPLACE PROCEDURE Call_Scaling_Factor (p_Settlement_Case_ID binary_integer, p_Profile_Types VARCHAR2, p_User VARCHAR2, p_Password VARCHAR2, p_Database VARCHAR2) AS EXTERNAL LIBRARY libscf
NAME "ScalingFactor"
LANGUAGE C
PARAMETERS (p_Settlement_Case_ID long, p_Profile_Types string,p_User string, p_Password string,p_Database string);

begin
Call_Scaling_Factor (1,'NSLS','AP_OWNER','AP_OWNER', 'AP_CONS'); end; Received on Fri Aug 05 2005 - 12:59:05 CDT