We haven't tested Scan&Solve in anything newer than Rhino V4 (WinXP & Win7), but at least one person has reported success running the Scan&Solve plugin in Rhino V5 x64. Please try it and let us know.
We are focusing our limited resources on getting things stable within the current commercial version of Rhino. I'm sure we will release a 64 bit version, but I don't anticipate it will be in a timeframe anyone would consider "soon". :-)