Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/359c81374e2a792d7e84759b9d41c8be.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563