This error can e.g. happen in combination with Infragistics NetAdvantage product.
In my case, previously I had added some NetAdvantage controls to a Visual Studio C# project and deleted them afterwards, including the references.
The project compiled without problems, until I upgraded to the latest NetAdvantage version on my workstation (and deleted the old version).
When the upgrade was finished, I couldn’t compile my project any more, but it didn’t even contain Infragistics controls.
Look for the file „licenses.licx“ in your project and remove it. NetAdvantage creates this file and it is not deleted automatically if you don’t have any IG DLL references in your project any more.
If you are currently using IG controls in the project, deleting the licenses file is not a good idea. In this case, run the Infragistics Version Utility, it should fix the problem.