[Solved] MyAchievements broke my forum

[Legitti]

How do i fix this pls, i really need it to work..

Code:

<error>
   <dateline>1456277061</dateline>
   <script>inc/functions.php</script>
   <line>971</line>
   <type>2</type>
   <friendly_type>Warning</friendly_type>
   <message>Cannot modify header information - headers already sent by (output started at /home/legickql/public_html/forum/inc/languages/english/myachievements.lang.php:131)</message>
</error>