If a resource is not available in a assembly or in satellite assemblies you will get a message like this "Could not find any resources appropriate for the specified culture...". You can open your assembly and any related satellite assemblies in ILDASM (tool that ships with the .NET framework). When your assembly is open in ILDASM take a look at the manifest file. This contains a list of the resources in your assembly. Usually such errors are the result of incorrect namespaces being used or from spelling errors.