Is there a 64 bit installer on the CD as well? With a 2010 date I would expect both would be available.
That said, if LeCroy doesn't get back to you and there's nothing else on the disk, you could try making a VM of a 32 bit OS (maybe XP), then passing the VM the USB connection and installing the drivers in the VM. Not the most elegant workaround in terms of workflow, but it's worked surprisingly well for me when interfacing with older equipment that communicates through standard busses (USB, serial, ethernet, etc.)