After I executed the terminal script Audirvana sent, the software ran for a time and then I started once again receiving the "file playback" error. I deleted the entire software package, reinstalled it, re-ran the script and...no luck.
I wrote to Audirvana a couple of weeks ago and after several days elapsed, I received a request from the company for the software log files and a IP address check which I provided. No reply so far.
I think Audirvana is tepid about continued support of the non-subscription version (i.e., the package you paid a "one time fee" to purchase) and is tacitly communicating that. I may try to build a Raspberry Pi with Moode or Volumio instead.
Anyway, I’m both stuck and disappointed...but, that’s the way it goes. If I get a helpful response, I’ll post it here.
Keith