You might try being more specific in configuring the location and name of your message.properties files. Try this:
You will probably need to change the path based on where your files are located. In my case, I have a messages directory under WEB-INF where I place my message files. You'll at least need to have your messages.properties file there as well as any locale specific instances in the form of messages_[locale_code].properties (as an example: messages_de.properties for the German locale), etc.
You are getting the message below because it can't even find the default message bundle.