A resource file should be a valid RESX file; XML, with a resmimetype, writer, and reader header.
<?xml version="1.0" encoding="utf-8"?>
<root>
<resheader name="resmimetype">
<value>text/microsoft-resx</value>
</resheader>
<resheader name="reader">
<value>System.Resources.ResXResourceReader</value>
</resheader>
<resheader name="writer">
<value>System.Resources.ResXResourceWriter</value>
</resheader>
<data name="King" xml:space="preserve">
<value>Koning</value>
</data>
<data name="Queen" xml:space="preserve">
<value>Koningin</value>
</data>
</root>