Erratic behaviour of Mbox 2 Pro with PT11

[nyjdams]

I've been trying to get my keyboard working with PT 11 that I recently purchased, and its been very erratic. I use an Mbox 2 pro, and I go to create a midi track, and sometimes the allowable inputs include "mbox 2 port 1". If it does, I can use the keyboard to trigger midi events. If not, I can't. This problem is related to the appearance of a box that says, at startup. "Some bus paths were made inactive" I can't say for sure if the midi probem occurs every time I get the bus path problem, but it seems connected.

Also - when the midi track is first created, and I route it to an aux track with a VI, no keystrokes (from my KX88) register anywhere until I record-enable the midi track. After that, everything works normally, even if I then take the midi track out of record mode.

And while I'm at it, if I create an instrument track, the allowable inputs so far have never included "mbox 2 port 1", so I have not yet succeeded in playing an instrument track with my keyboard. Weird.

Anyone able to shed some light on what's going on here?