I have the exact same problem as bellehard. I have Nitro v1.03. I have tried to re-authorize as suggested above, but it still says "not authorized" in the GLB window (and no sound is being processed). I have tried to re-install, thrash the preference file, etc... but it simply don't want to be authorized. I have tried both vst and Au, but the problem is the same: "not authorized". It seems to authorize fine, there is no message that says otherwise. I have tried both typing in the name and serial, and copy/paste it from the mail I got.
I would be very thankful if this problem could be solved.
I have also sent a mail to your support.
Kind regards,
Ulf S