Thanks. As described there is nothing that SONAR can do to prevent that behavior since the RME driver manages its state when same rates are changed by internally unloading and reloading its kernel mode components. I would argue that the message is somewhat useful since its telling you what happened, since without it you would never know why SONAR dropped out or took long. The whole purpose of the device change notifications that we added was to allow SONAR to detect device removal and allow SONAR to re-detect the new configuration dynamically. 
 
I'll see if I can repro the second case. AFIK I did not run into that.

...

I confess the level of knowledge here is now considerably in excess to the capacity of my brain.
Suffice it to say, am extremely glad the OP got sorted.
My similar sitch I confess seems presently ameliorated...either by random physical wigglings of my fw PCIe card molexes or my 17 times bitten, 18 times shy recent Dim Pro experiences resulting in me getting Kompakt to work, of all things..
   An odd piece of other randomness came up in my thrashings about for personal solutions: I was at the stage of throwing in the fw towel and simply grabbing the drivers to allow my Delta 66 to work, when I noticed way down in the drivers' small print that "several Avid users have reported that with W7 64 SP1(sic?), their Delta 66 will disconnect" after approximately 30 minutes....
  The "workaround" seeemingly is to shut down their DAW(presumably PT), then fire it up again.
Now, I know jack about the arcane mysteries of Windows, but I'm furrowing my brow just wondering if there are some oddities with W7 and how it manages its audio, that given the right(ie, wrong) conditions, present similar "disconnect" scenarios.
  I'm not wishing a reply particularly, as I realise this thread may have run its effective course.
[I'm also maybe teetering on the edge of biting my own head off, as W7 will both allow me to burn a CD, and rip back what it burnt...yet refuses to play the very CD its been successfully mauling about, whining about a flippin' codec for doing so....so please ignore me, as I've a nervous breakdown to return to...]

I was going to suggest that maybe other hosts handle the message invisibly: eg. they do the equivalent of pressing "no" after a short delay if they receive this message, and only fail if this doesn't work.  Would that be an option for SONAR?

The great Jazz Musician, Noel B.!!
We'll see if the sensing behavior can be improved in the future.

Nice one, Noel! Thanks for being open to ideas.

Noel Borthwick [Cakewalk]
We'll see if the sensing behavior can be improved in the future.

where's that Like button...  ;)