Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/39b5851f716a75ea6e50f9d2acf88df4.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563