Configuration :: ResourceManager And Resx Files - Files To Display Items In Multiple Languages

I have an application that uses resource files to display items in multiple languages. My app uses quote a lot of javascript and the alerts need to display in the local language. To do this, I have created an http handler which will read the keys and values of the culture-specific resource file and write them to a JSON array which is then embedded in the page in a script tag, the messages can then be accesses using, for exmaple:

Message.Error (en-GB = "Error", fr-FR = "Erreur")

The messages http handler works great in development, however when I run the application on a test server, I get the error: Could not find any resources appropriate for the specified culture or the neutral culture. Make sure "Resources.Alerts.resources" was correctly embedded or linked into assembly "App_GlobalResources.b0n9j90e" at compile time, or that all the satellite assemblies required are loadable and fully signed. The code that I use to acccess the resource file is:

ResourceManager manager = Resources.Alerts.ResourceManager;
ResourceSet resourceSet= Resources.Alerts.ResourceManager.GetResourceSet(Thread.CurrentThread.CurrentCulture, true, true);

Where Resources.Alerts is the type that contains my multi-lingual definitions. The build action for the Alerts.resx file is set to "Embedded Resource". Any ideas why this works locally but not on my test server, am I missing something?