Hi yamahalover,
.ppi files can ONLY be imported directly to the keyboard and ONLY to the specific model (Genos, Tyros5, PSR-S975/970/775/770/670) for which the .ppi file was originally created (in YEM).
.ppi files can NOT be "back-imported" to YEM, and there is NO way to convert a .ppi file to a .ppf file (to use with YEM).
Best regards,
Chris