A new private test build released:
http://www.macecraft.com/downloads/betas/jv16pt_setup_555.exe
This version should fix the remaining x64 compatibility issues reported. However, there is at least one more compatibility issue left: when using PowerTools' Open in RegEdit feature under 64 bit Windows the started instance of RegEdit is 32 bit and thus only displays the 32 bit registry, not the full registry.