Hi madakaben,
export the Instrument Info file (.n27) again from your keyboard onto a USB stick, and be sure that this is the ONLY .n27 file on the stick. Then connect the stick to the computer and try to import the file again as Install Target in YEM.
P.S.
Make sure that you have the latest version of Expansion Manager (YEM) installed on your computer (currently V2.7.0).
Best regards,
Chris