We have one pc in the company with Land Desktop 3 installed. We have been using it for many years without any issues until recently (11 Oct 12) after installation of Norton Internet Security 2013, an authorization popout window (the one you see during the first installation) appears suddenly with the follow message:
IMPORTANT! In order to contnue, you must obtain additional authorization. Error 
(11 Oct 12) Initially we thought it is probably a minor hiccup due to the Norton Internet Security 2013, we called Autodesk and managed to reauthorize it with the code emailed to us.
(19 Nov 12) However, after using it for about a month, the same problem appeared again. requesting for reauthorization. We called Autodesk to reauthorize again.
(23 Nov 12) Same problem again. We thought the software might have a conflict with NIS2013, hence, we removed NIS2013 completely and replaced it with Kaspersky Internet Security 2013. We called Autodesk to reauthorize again.
(26 Nov 12) Same problem again. Popout window appear requesting for authorization again. We decided not to call Autodesk for now as we believe the same problem will occur again. Something needs to be fixed before reauthorization again.
I would appreciate if anyone could provide some advices to us.