Cannot modify header information

[ming]

sorry , I have some problem.

I used XAMPP for Windows Version 1.5.0-pl1 , but run my program ,
it to appear the
" Warning: Cannot modify header information - headers already sent by (output started at D:\xampp\htdocs\radius\login_more_check.php:4) in D:\xampp\htdocs\radius\login_more_check.php on line 131 "

I do'nt know why happen this question ,
can some boddy help me ..

thanks a lot

[KingCrunch]

Youve tried to send headers (in PHP by "header()" or "setcookie") after headers have already been sent. Headers were sent just before the body begins. If you alerady something to the Browser ("echo","print","var_dump") the headers are already sent and you are not allowed to send some more or other headers.
If you want to set headers, you have to make sure, that they are the very first, before any other information will be sent to the Browser. Or you can prevent PHP from sending something to the Browser with "ob_start" (see PHP-Manual)

You understand me?

[ming]

Thanks a lot