Both host and slave must be 64 bit...
My ReWire host is 64-bit but I can't seem to ReWire Reason to it, what gives?
While ReWire 64-bit is included in with Reason 6 and Reason Essentials it also needs to be implemented in the ReWire host software. Please contact the manufacturer of your host to see if they support ReWire 64-bit.
Is ReWire 64-bit compatible?
Just as the current versions of Reason and Reason Essentials, ReWire is 64-bit too. Note that 64-bit ReWire needs to be implemented in both the slave application (Reason, Reason Essentials) and your host. Please contact the manufacturer of your ReWire host of choice for compatibility information.