I kept having problems with licences on blank 5.1(.1) installations on my Windows XP machine. I use VS.NET IIS Admin to create my sites in IIS which worked correctly all the time. Haven’t created any new projects since I’ve installed VS.NET 2005 and .NET 2.0. From that moment a ‘Missing License’-error appeard. This morning, I finially figured out that the default .NET version of a new IIS-Site is set to 2.0 instead of 1.1. You can see on the screenshot below how to fix this(you have to do it everythime you create a new site).