Mapnik, Ubuntu

I am trying to install mapnik and generate tiles for a given country using this tutorial

http://weait.com/content/build-your-own-openstreetmap-server

But what a pity thing. Despite I have downloaded all boundary files and unpacked it , but a strange error is disturbing me to do it .

root@ks356390:/home/bin/mapnik# sudo ./generate_image.py Traceback
(most recent call last):   File "./generate_image.py", line 42, in
<module>
    mapnik.load_map(m,mapfile) RuntimeError:
/home/bin/mapnik/world_boundaries/10m_populated_places does not exist
(encountered during parsing of layer 'nepopulated')

but see ...

root@ks356390:/home/bin/mapnik# cd world_boundaries
Sie haben neue Post in /var/mail/root.
root@ks356390:/home/bin/mapnik/world_boundaries# ls
10m_populated_places                      places.shx
110m_admin_0_boundary_lines_land.dbf      processed_p.dbf
110m_admin_0_boundary_lines_land.prj      processed_p.index
110m_admin_0_boundary_lines_land.sbn      processed_p.shp
110m_admin_0_boundary_lines_land.sbx      processed_p.shx
110m_admin_0_boundary_lines_land.shp      shoreline_300.dbf
110m_admin_0_boundary_lines_land.shp.xml  shoreline_300.index
110m_admin_0_boundary_lines_land.shx      shoreline_300.shp
builtup_area.dbf                          shoreline_300.shx
builtup_area.index                        world_bnd_m.dbf
builtup_area.prj                          world_bnd_m.index
builtup_area.shp                          world_bnd_m.prj
builtup_area.shx                          world_bnd_m.shp
ne_10m_populated_places.dbf               world_bnd_m.shx
ne_10m_populated_places.prj               world_boundaries_m.dbf
ne_10m_populated_places.shp               world_boundaries_m.index
ne_10m_populated_places.shx               world_boundaries_m.prj
places.dbf                                world_boundaries_m.shp
places.prj                                world_boundaries_m.shx
places.shp root@ks356390:/home/bin/mapnik/world_boundaries#

I tried to make generate_image with sudo also... Any idea why mapnik is making this in ubuntu??????? It seems it doesn't see 10M nepopulated , despite the folder and files exist