How to change the url adress?

[eluser]Rubiz'[/eluser]
Well, I discovered that it was an "echo" I had put for debugging, but problem persists, cause I have another error when the page reloads:

A PHP Error was encountered

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at /home/bandeira/public_html/email_sender/system/application/controllers/sender.php:64)

Filename: helpers/url_helper.php

Line Number: 487