Hi Kingcake,
You asked "Is there something more to it than the extension?" The answer is Yes, there is.
The Text Encoding Converter uses plug-ins, which are code fragments containing the information required to perform a conversion. A
plug-in can handle one or more types of conversions. Plug-ins are the true conversion engines. The Text Encoding Converter provides a uniform conversion protocol, but includes no implementation for any specific kind of conversion. In other words, it supplies a generic framework for conversion but does none of the conversion work itself; rather, the plug-ins perform the actual conversions.
The necessary plug-ins are (or should be) in the "Text Encodings" folder, within your System Folder. Check to make sure that folder is present and that it contains 15 plug-ins.
Hope this helps,
bottles