It doesn't look like all chipsets are supported yet. If you chipset isn't a certain one the driver throws an X error and stops the server startup.
The Mobility X1300 isn't supported. Looking at ati_id.c there are 4 different PCI Ids for such a card; not sure which mine is. If someone knows how to get that it'd be appreciated.
Also it mentions a mailing list; anyone know where that mailing list is and where to subscribe?