Permission denied, even with 777 permission.

[Vingtoft]

Been trying to wrap my head around this error for a few hours without any luck.
When I follow the instructions defined in the readme, I get the following error:

Warning: include(/var/www/html/rainloop/v/1.10.1.127/include.php): failed to open stream: Permission denied in /var/www/html/index.php on line 16

Warning: include(): Failed opening '/var/www/html/rainloop/v/1.10.1.127/include.php' for inclusion (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/html/index.php on line 16

I'm pretty sure that all permissions are set correctly, because I have executed the following two commands:
chmod -R 777 /var
chown -R www-data:www-data /var

The only modification I have made is that I print out the errors.

Please help, thanks