An attempt to work in parallel with UNICODE, ASCII and Multibyte string (UTF8) is not a good choice. You will never localize the problem for user “¿¿¿¿¿¿¿” or “¿¿¿¿”, but the problem could really happen!
The file deploy/src/common/windows/native/Platform.cpp, the function Java_com_sun_deploy_config_WinPlatform_getPlatformUserHome returns ASCII path only. Naturally NT kernel is UNICODE, so by using ASCII we have a parameters conversion penalty.