i can certianly help out regarding Nikon scanners on X64.
I have a LS-5000 and this was found not to work on Vista x64. nikon did not support 64 bit drivers.
the way round (and this is not an offial route!) is to go to
http://www.hamrick.com/
and download the software which is free. What you need to do is install the nikon scan software but don't specify that you want to install the drivers for any of the scanners it suggest. If you then installvuscan , that will inturn install drivers for a multitude of scanners , hopefully including the one you have. Go inot device driver and for the scanner that does not have a driver installed fo it, install adriver but point to the inf file that vuscan installs. hey presto, the scanner is recognised.
basically just boils down to a an inf file to fix it.
it occasionally fails in that nikon scan occasionslly loses sigh of the scanner but Idespite that I've managed to scan a large number of slides already.
i don;'t know if this works under XP X64 but I reckon the chances are good that it would.