Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/04b1b5a798db871464cfb9b0faf47a5d.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563