[Observium] Installation help with menu items

Hi - I have a new installation of observium running on apache on gentoo. When I go to the main page (http://myserver/observium/html/) it looks similar to the demo and I see the data.

But, when I click on the menu items, they don't work. For example, if I click on Locations I get The requested URL /index.php/locations// was not found on this server.

Any ideas as to what I've configured incorrectly?

Thanks Dave