Interesting. I downloaded RAVedit1_0.exe from this site, and it's not the same as RAVeditSetup1_0.exe as on Yamaha's site. The one on this site is far more helpful in that it actually displays an error message that says "Unsupported 16-bit Application. The program ...setup.exe cannot start or run due to incompatibility with 64-bit versions of Windows. Please contact the software vendor to ask if a 64-bit Windows compatible version is available." It may be that the editor itself id 32-bit but the installer is 16-bit.

But as you said, ProntoEdit runs fine. Is there any reason I can't use ProntoEdit?