I have installed AutoCAD LT 2008 with stan alone license, everything works fine license was activated on the Internet.
The program works without a problem until connecting any USB flash drive, and then AutoCAD shows the lack of a license. To fix this error I have to re-activate the program.
I have a HP Pavilion HDX9000 computer working on Vista 64 Bit.
Make sure that your application is up-to-date. Check here:
http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=5620053&linkID=9240618
I installed the patch, and then AutoCAD displays the message "verifying licenses" and all work properly. When I turned on the computer the next day I received the message about the license has expired and I need a new activation code.