Ok, this will seem freaky, but...

EVEN when I had Amplitube 3 registered and there was no Amplitube 4 and I was using it in Real Band, I got the white noise problem when I rendered a song. Even though the product was registered.

There did not seem to be a solution from anyone.

SO, I experimented: I put an amplifier (same with ALL IK products) on a BLANK track.

Do not ask me why, but with the product I was using also loaded on a blank track I no longer had white noise and everything worked.

Have no explanation, but that is what I did as a REGISTERED user.

Hope you get it going. I use Amplitube 4 in another DAW and it is a phenomenal tool.