DMS Doctor is failing because the program relies on an internet connection to Phatnoise, and their servers seem to be down for more than a month now. So, the particular failure message you're getting does not indicate anything particularly wrong with your DMS. (I get the same message and my DMS works fine.)
This is also why you haven't been able to download anything else, even the firmware updates, from Phatnoise.
To use the firmware files you downloaded, unzip all the files to your phtsys partition. Then, carefully follow the instructions starting from page 46 of your Phatbox manual to update the firmware in your car. See if that does not fix your problem.
If that does not work, I would also suggest using the option in Music Manager to "fix DMS database," which is found by clicking on hardware options, then to DMS database/voice prompts. If even that does not work, post again!