Support for that camera was added in version 7.2. How are you trying to use the converter? You don't see the actual files listed in the folder. You just choose the folder containing your original raw files. Have you done that?
I have been using DNG converter on Canon files for some time, but I forgot that minor detail - that the files are not listed until you start the conversion process.
Another senior "grey moment"...
I'm also having a problem with files from the FZ200. I can successfully convert the RW2 files to .DNG using the converter. However, when i try to import the new .DNG file into GIMP 2.8, it is imported at 256x192 pixels. it is still 11mg or so, but the resolution is poor. Does anyone know how to import converted RAW files into GIMP?