BuddyPress.org

hello I’ve made some changes and now my functions.php in the theme folder doesnt work :

functions.php is:
function my_member_username() {
global $members_template;
return $members_template->member->user_login;
}
add_filter(‘bp_member_name’,’my_member_username’);

I get this error:
Warning: Cannot modify header information – headers already sent by (output started at /home……themes/…functions.php:14) in /homez.139/name/www/wp-login.php on line 337

but thats not the only error I get the same but on other lines.