Did you use the correct version of the AutomaticUpdater control? Tell me which version of the AutomaticUpdater.dll you added to the toolbox.
For instance, if you used the .NET 4.0 version of the AutomaticUpdater control in a .NET 2.0, 3.0, or 3.5 app you'll get that error. The same if you used the .NET 2.0+ of the AutomaticUpdater control in a .NET 4.0 app.
Also, note that the .NET 4.0 version of the AutomaticUpdater requires the full .NET 4.0 framework (Read this). In wyBuild 2.6 the AutomaticUpdater will be compatible with .NET 4.0 Client Profile, but right now it requires the full framework.