Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/08347f29d1a3d1c05fbf95d9b956c973.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563