FYI: I just downloaded and installed IDEA EAP 10781 using the the Windows exe installer. When I got the Complete Installation dialog prompt to import settings from a previous version,m none of my prior installs were validated as a proper installation directory.
I believe a possible cause of this might be that I changed the location of my idea.config.path and idea.system.path to another local drive that had plenty of extra space. (The IDEA config files and caches were maxing out my boot drive.) Maybe the installer is looking in user home and not finding the .IntelliJIdea8x directory?
I ended up selecting the "Don't import settings" option to allow the install to complete.