I actually solved this problem and I solved it by commenting on line 44 of the plugins/bp-create-group-type/admin/css/bp-add-group-types-admin.css (margin: 0px 5%;)
Estava com esse mesmo problema e resolvi colocando algumas regras no Nginx para aceita CORS. Usei essa sugestão http://blog.osteel.me/posts/2015/07/19/handling-cors-with-nginx.html
