Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/fedb1815432b9ea5005e49fe4ed1b2c4.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563