Update V1R3.1 won't install on Windows8 64-bit; yes, it's error code 1320 again!

Update V1R3.1 gives error 1320 path too long during installation on a 64-bit Windows8 system.

I've already tried the "move Application Data directory" solution, but Windows8 doesn't have an "Application Data" directory: so I've tried other possibly related directories to no avail.

Anyone know how to fix this Windows8 issue?