Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/c3544c838be6ce0f7d7722d22d108c43.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563