Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/1c6298c24ea2600adcd2b5636a6ebd84.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563