DevOps, CI/CD and Automation

I have a dll,which writed by vc++60.I am doing exeperiments about external procedure call.I have write some PL/SQL code which is according to oracle sample,but when we run it,there are some errors:
SQL> @sample

?bRQ44=(!#


3LPr0|RQ44=(!#

C;SP4mNs!#

3LPr0|VwLeRQ44=(!#

C;SP4mNs!#
BEGIN demopack.demo_procedure; END;

*
ERROR N;SZ5Z 1 PP:
ORA-28595: Extproc agent : Invalid DLL Path
ORA-06512: TZ"SYSTEM.DEMOPACK", line 11
ORA-06512: TZ"SYSTEM.DEMOPACK", line 11
ORA-06512: TZline 1



3LPr0|VwLeRQ44=(!#

I have look through internet about this error,but I have not correct this error.
my platform:windows 2000 server
oracle:9.2 personal edition
my sql program as follow:
create or replace library samplelib is 'e:oracle\ora92\bin\sample.dll';
/
create or replace package demopack is

procedure sampleBeep;

procedure sampleDelay;

procedure demo_procedure;

end demopack;
/
show errors

create or replace package body demopack is

procedure sampleBeep is external name "sampleBeep" library samplelib;

procedure sampleDelay is external name "sampleDelay" library samplelib;

procedure demo_procedure is

begin

demopack.sampleBeep;
demopack.sampleDelay;
demopack.sampleBeep;

end demo_procedure;

end demopack;
/
show errors
execute demopack.demo_procedure;
/

please tell me how to correct this problem,I need detailed information.
please help me !!!!
give me detailed example about listener.ora and tnsname.ora,and tell me detailed step how to correct problem.
It is important to me .