Help on Single Sign On

Hi,
I configured and set up the SSO (single sign on) to access my Web server.

S.O: Linux
Web Server: Apache

Below the steps:

- Configured the Policy Domain and create a new Authentication Scheme on Oracle Access Manager
- Modify the http.conf file and add the rows:
ProxyPass /dbcenter/entry.php      !
ProxyPass /dbcenter/login.php      !

- Create the file: entry.php  - login.php - myweb.php  (see attached files)

Now when I try to connect at my portal web: http://10.11.12.33/myweb.php I get this warning:

Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/dbcenter/login.php:3) in /var/www/html/dbcenter/login.php on line 24

and then successfully entered


Have any idea how to avoid this warning?
entry.php
login.php
myweb.php