Hi Gokhan,
I am sorry for the delay of this reply.
Regarding your issue, look like in your language file 'JOOMLA/administrator/language/tr-TR/tr-TR.plg_app_user_profiles.ini', you required two variables to be parsed but in EasySocial, we actually passed in one variable only.
APP_USER_PROFILES_STREAM_REGISTERED="%1s, Edusosyal'e kayıt oldu. Aramıza hoşgeldin %1s"
So what i did is to replaced the above string with following:
APP_USER_PROFILES_STREAM_REGISTERED="%1s just registered on the site"
For your information, this string is calling at file 'JOOMLA/media/com_easysocial/apps/user/profiles/themes/default/streams/register.title.php'.
Hope this help and have a nice day