[Tilesathome] howto generate lowzoom tiles

[Raphael Studer]

Hi,

I tried to generate some lowzoom tiles.
I want to generate this tile:
http://dev.openstreetmap.org/~ojw/Tiles/tile.php/11/925/856.png

so i tried:
lowzoom.pl 925 856 11 12

the files get downloaded and merged, but the result is a 69 byte png.
What am I doing wrong?

Regards

Raphael