John,
Re-read what Hendrick said above. His advice seems like it's probably what's going on in your situation. As far as I know, dolby decoding doesn't require any plugins or configuration. Other than getting you OUTPUT FORMAT setup correctly. This will apply to all audio, including DTS, PCM, DSD, FLAC, etc.
If you need help, post a screen shot of your Output Format settings in the DSP Studio and we should be able to guide you along.
Good luck!
Brian.