There is a 64 Bit driver on the website. Navigating from this page,
(http://www.rolanddga.com/owners/support/productList.asp) simply choose the GX-24, then choose Setup/Install Guides. On that list, there is a readme file that outlines the procedure to install the driver in
Windows 7, since it is not plug and play. Once you have that, download the driver from the pull down Drivers list on the same page.
It is still in beta, but we have been running it for some time here, and have had no issues with Vista 64 Bit. We have also had good luck with
Windows 7, despite the somewhat convoluted installation procedure.
Hope that helps.