[maxmsp] can't figure out my MIDI setup

Help!  I'm trying to work my way through the tutorials and I can't sort out my MIDI setup.  I"m on tutorial 12.

My setup:
iMac 10.5
Max 4.6
Access Virus TI via USB

Max is receiving MIDI from the Virus, no problem...it's doing so even when I had not assigned the Virus to Abbrev "a", which, to my understanding, it should actually NOT do since the tutorial patch specifies "notein a".

Furthermore, I can't get any sound out of the Virus via Max.  I set the Abbrev to A, no offset, turned off the other devices, made sure it set to receive channel 1...can't get a thing.

Further weirdness: in Max's MIDI setup window, I can deselect every input and output device, and Max is still receiving the note messages from the Virus' keyboard.

Everything looks to be in order in the Mac's MIDI Setup as well.

Any suggestions?