i can browse through one of my categories, electric rifles, without a problem, but when i try to go to other categories i get this error.

Warning: Cannot modify header information - headers already sent by (output started at /home/airinfan/public_html/catalog/includes/languages/english/airinfantry/index.php:117) in /home/airinfan/public_html/catalog/includes/functions/functions_general.php on line 44

i can click and go to a category if there are no items in it however. could this problem be caused by either easy populate or cross sell? and how can i fix it?

my url is www.airinfantry.com/catalog