Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/32c8c72e96ea4c4228ff6f451e0b1311.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563