Hi Kreative,
i think your problem is midi related, to be sure, do this:
in sonar or any other daw, draw some midi notes in PRV. but don't use your keyboard at all, you can even turn it off.
try sustain notes and lots of variations, and if with this manner every thing is fine, then your problem is a midi related one, maybe an unwanted CC changes...

Hi Kreative,
 
i think your problem is a MIDI related one.
 to be sure, draw some midi notes with different velocities and different variations, but don't use your midi controller to draw notes, use PRV tools instead, and even turn-off your midi controller or disconnect it.

if it helps and your problem were solved, then there is something wrong with your midi controller , maybe an unwanted CC massage...

 
i hope it helps.

eSATA is the culprit. I switched to a USB 2 cable and its all good.  I don't know why or how, but I can't use eSATA because it does not cooperate with my system for some reason. It may be faster, but it hardly matters when it doesn't get the job done right.

Everything works fine, now.

Mission accomplished! Thanks for the encouragement. I should have tried it long ago, but I thought it just couldn't be, even though I suspected it was possible from the beginning.

Ahhh, interesting. Glad you were able to solve the problem!

I'm pretty impressed that you were able to stick with it and solve the problem--there's not a lot of support for tricky problems like that online. Hopefully troubleshooting the problem didn't put your music out of commission for too long.