Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/eb5c2af4162d3a25127a2702f7e19034.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563