Il programma si istalla correttemente, ma Autotune non si istalla.
Qualcuno può dirmi come posso rimediare?

The program installs correctly, but Autotune does not install.
Can someone tell me how I can fix it?

Autotune does not support Audacity.
There is a list of supported host applications on their website:

I think that the 32-bit VST version of GSnap should work, though the MIDI features are not supported by Audacity:

The pitch-correction part of Graillon2 (free version) works in Audacity in Windows …