Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/fb33d395605f8d9da5329d2593de5aba.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563