Silent Buses Detected notice, so no sound

Can't figure out what to do to stop getting the "Silent Buses Detected" notice in X1, which says:
"The following tracks and buses are currently assigned to a silent hardware output.  The items listed below will be silent in your project until their outputs are reassigned to an appropriate hardware output."
 
And of course it is correct.....I cannot get any playback of that song.  There is a help file which indicates some of the possible causes, but gives no solutions, and I can't find any of the problems that it refers to.  I have a couple instances of TTS1 inserted and selected as the output for a total of 32 MIDI tracks.
 
I am using an M-Audio Fast Track Pro as my interface.  It is working fine, as I have no problem playing other music, and I can also play other songs in Sonar.  I'm using Windows XP.  I have rebooted everything.
 
Anybody have an idea what the llikely cause of this message is?  Thanks.
 

At least one of your buses is routed somewhere other than your master bus, another bus or main outs.  It's probably been routed to one of the unused outputs on your soundcard.  You can select any of your soundcard's outputs, but only one stereo pair is your main out (such as Play 1 left/right).  I used to purposely route a bus or two to an unused output on my soundcard when I wanted to keep it, but not hear it (instead of muting).  It was possible to turn off that warning in 8.5, but no longer possible in X1, so you just can't send a bus to a soundcard output other than your main outs without the warning every time you launch Sonar X1 & X2.

TTS-1 does not support 88.2 Sample Rates.  I don't know if that has anything to do with THIS issue for you, but maybe it is worth checking to make sure it isn't what is happening.
 
Check the Sample Rate in Preferences>Audio>(then either Device Settings or Playback and Recording - not near computer with Sonar at the moment, but it is one of those two - me thinks).
 
Bob Bone

Odd, worked for me in X1 when I had a project with the silent bus error showing up. I added it after reading a post from Noel to someone having the same problem in X1.