generate_tiles.py problem

Greetings,

I've installed PostGreSQL and PostGIS and sucessfully loaded Ireland (ireland.osm) into the database.

I've tried doing the following:

source set-mapnik-env
./customize-mapnik-map > $MAPNIK_MAP_FILE
./generate_tiles.py

(I've edited set-mapnik-env and generate_tiles as appropriate)

The problem is, when I run 'generate_tiles.py' - nothing happens! No error messages, nothing, it just quits after a split-second.

I'm completely stumped and have no idea what to do now.

Could anyone give me any suggestions?

Many thanks,