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Warning: call_user_func_array() expects parameter 1 to be a valid callback, class 'CommunityPhotosController' does not have a method 'ajaxChangeCover' in /home/alfer194/public_html/components/com_community/community.php on line 265
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Seems your code already broken, I need FTP access for inspecting this issue further, can you provide it please?
I see, i know the problem.. but I suggest you re-install your Jomsocial via iJoomla installer by click override button.. it will help for making sure everything will work again.. and dont forget to backup your work