So, I downloaded the 64-bit version of the 3.1 for Windows. Firstly, I doesn’t let me choose the installation path. It’s defined to “C:\Program Files\jmonkeyplatform” and there’s no way to change it. And it just installs blender! A folder named 2.57 and a bunch of DLL’s. Please fix it guys!
My installer checksum (using fciv and MD5) is d51f569b6b9b3958dbc0e9b1af39283f.