Nginx Strtolower Problem With Fpm Handler

hi all when i tried change php handler to fpm i am getting strtolower problem like this

Warning: require(/var/www/vhosts/ failed to open stream: No such file or directory in /var/www/vhosts/ on line 76

my language is turkish check fn.ultImate.php is not fn.ultimate.php doesnt lower I to i. when i manually edit. smarty libs getting same problem.

any help ?

fixed with setlocale(LC_ALL, "en_US.UTF-8");