PostGIS/osm example error

[cledantec]

I've installed all the required pieces and gotten things close to up and running for rending svg maps from and postgis osm dump. But, when I run things, kartograph crunchs for a while then dumps with this error:

cli.py, in render_map()
71: K.generate(cfg, args.output, preview=args.preview, format=format, stylesheet=css) kartograph.py, in generate()
46: _map = Map(opts, self.layerCache, format=format) map.py, in init()
61: layer.get_features() maplayer.py, in get_features()
81: charset=layer.options['charset'] layersource/postgislayer.py, in get_features()
64: cur.execute('SELECT "%s" FROM %s WHERE %s' % ('", "'.join(fields), self.table, query))
Operation on mixed SRID geometries

Is this a kartograph bug? A Postgres/PostGIS issue? This error occurs whether I try rendering the map I want or following the example provided on line.

Any help appreciated.