mod_tile help needed

Hi all

Newbie here. I have followed the excellent tutorial http://switch2osm.org/serving-tiles/manually-building-a-tile-server/

and have a tile server working with an extract of Luxembourg loaded from http://download.geofabrik.de/osm/

My basic OpenLayers page works and is displaying a map of the world at level 0 from http://myserver/osm_tiles2/0/0/0.png. However I can’t figure how to render the rest of the tiles including Luxembourg. When I zoom down the levels no map data is shown.

Any pointers gratefully received.