There are multiple revisions of the DWL-G630, each with revision specific drivers, firmware, installation guides, and other resources.
http://www.dlink.com/products/?pid=dwl-g630&tab=3
Click on your location first, then your specific model number, then on the link "Drivers".
FYI, this product is
End of Life as of January 01, 2009 in the US.