Hey all,
First of all my apologies if this is in the wrong forum, and I did send an email to the support regarding the issue but I thought I could get faster feedback from the users/mods here. 
Yesterday I bought 4 licenses of the "BitDefender Internet Security 2011 (3 PCs - 1 Year), and I received the 4 keys via email (each key for 3 computers) to install on 12 computers at our office.
9 desktops with Windows XP SP3, 1 desktop with Windows 7 64bit, 2 Laptops with Windows Vista and 1 Laptop with Windows XP SP3.
So far I've installed the product on 4 dekstops and 1 laptop using Windows Xp with no problems whatsoever, the problem started when I tried installing the program on Windows Vista.
The installation goes fine until the update segment, after it updates and finishes installation I get the message "Register / Buy now" message. So I enter the key and I'm informed that the key is not for the installed product so I click on "Install BitDefender Internet Security 2011 instead" option and it accepts the key. After I enter the username/password for the account (I'm going to use the same account for all 12 computers) I get the same error all over again.
So I'm quite clueless, and I tried uninstalling and reinstalling without any success. Could anyone help as now I have one computer on the network that is not protected??
Oh one other thing, one of the keys I installed reported that it was valid for 7xx days instead of 365 days, does that mean it used 2 PCs instead of 1?
Thank you all for taking the time to read this long message, and I hope I hear from anyone soon regarding the issue. 
Regards,
Negad