Configure DAD to call stored procedure from Internet Explorer

After installing Oracle 9.01 Enterprise Sever (Windows OS), I created an user named xuanthu and created some table and a procedure 'Helo' (by CREATE TABLE....). Now i want to call Helo from Internet Explorer. I open Pl/SQL gateway and create an DAD with the following configuration:
(Oracle server is running on my computer)

Database Access Descriptor Name: myDAD
UserName:xuanthu
Password:****
ConnectString: localhost:1521:tinysid

(the following is default options given by DAD wizard)
Authentication Mod: Single-signon
Session Cookie: (blank)
Package/Session Management Type: Stateless Enable Connection Pooling? yes
Document Table : XuanThu .wwdoc_document Document Access Path: docs
Document Access Procedure: XuanThu .wwdoc_process.process_download Extensions to be uploaded as Long Raw: blank Path Alias : url
Path Alias Procedure : XuanThu .wwpth_api_alias.process_download

In internet explorer, i call: http://localhost/pls/mydad/helo . I just received this message:
"Service Temporarily Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later. "

File Oracle9i\Apache\Apache\logs\error_log show that: [Fri Nov 28 20:52:59 2003] [error] mod_plsql: /pls/mydad/helo HTTP-503 ORA-12560 <B>Proxy log On failed.</B><BR>Please verify that you have specified correct connectivity information i.e. username, password & connect-string in the DAD

WHAT'S WRONG ? Can anyone help me ?

(Oh, I'm sure that my Database SID (declared in ConnecString is TinySID).
But if i want to check it again (ie. get the SID of the database), how to do it (by wizard or SQL command) ?

Thanks alot and alot ! Received on Fri Nov 28 2003 - 08:11:09 CST