Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/e763a2ae9fee9afde0f4a5a87b4a4523.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563