Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/e32bb04322fd8e1b42bb2bc2ce3b9392.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563