Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/e2962e4af4e7d4063f41eb28df6f9ea6.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563