Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/58476e3ba80c33fd8d79b567cb7d6b95.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563