Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/49fb7657f6e76611ca2c577ac2f3f8bf.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563