I have tried to fix this but just don't know enough about php.

When I go to the final checkout page it is blank. I ran the error mydebug report and and this is the error I got:

[10-Mar-2010 16:41:41] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/content/02/4740502/html/personalizeddrumsticks/zencart/includes/languages/english/modules/shipping/flat.php:53) in /home/content/02/4740502/html/personalizeddrumsticks/zencart/includes/functions/functions_general.php on line 44



Does anyone have any idea how to fix this?