Hi. Just a little more information on the error.
Fortunately, I was prepared for the night my machine might die, so I had a spare Remstar Auto ready to go. I plugged it into the Remstar heated humidifier and it worked perfectly.
I decided to play around with the machine giving the error code. If I plug it in w/o the humidifier, it seem to work fine (at least it blows air and gives no error code). Plug it in through the humidifier and the error shows up.
Odd, to say the least.