Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/60ec21f1c1c92a422ce73a2a497d385d.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563