cannot add header

[joyce]

why am i getting this error??


Warning: Cannot add header information - headers already sent by (output started at c:/inetpub/wwwroot/vbulletin2.2.5/progress.php:1) in c:\inetpub\wwwroot\vbulletin2.2.5\admin\functions. php on line 1617


my first line is

require ("./global.php");


pls help.

[Admin]

Make sure you have no white spaces or new lines before <?php.