The Compact Framework Edition uses a license that is different than the license used on Developer or Single Editions. The Developer/Single Edition license cannot be used on the Compact Framework Edition and vice-versa.
When you've purchase NET.ABLINKCF you will receive a Development license (nablcfdev.lic) and Activation Code:
Adding Development License File
Open your Visual Studio.NET 2005/2008 Smart Device project
In the Solution Explorer window select ( Add | Add Existing Item… )
Select the nabl30cfdev.lic license file
Select the Properties of file
Set Build Action = Content
Set Copy to Output Directory = Copy Always
Build your application and deploy it to a Compact Framework Device, or Emulator.
Debug or run your Compact Framework application.
You will see an activation dialog box
Enter your activation code and press the Activate button