Sorry for the delay in replying, all. I thought I had my profile set so that I would get an e-mail when there was a reply, but apparently not.
Anyway, I will work on all of your suggestions and let you know what happens.
I DO load Kontakt as the soft synth, and I DO load Session Horns as the instrument. I then direct the MIDI stream for the horn part(s) I want to use to Kontakt. That's where the whole thing fails.
I can use the on-screen keyboard to "play" the horn section, so the instrument seems to be loading up ok. I just don't know why it won't play back the MIDI stream.
I'm viewing the tutorial as I type this, so maybe that will give me the answer.
Thanks very much for your help, and I'll let you all know if this becomes "solved" at some point.
- DR