if you boot up your computer with an arbitrary midi i/o configuration does it run until you change it? Or does it only run with one specific configuration? And if you run it with one configuration, shut the performance too down completely, change the configuration, and then start it again, does it run then? Or does that change cause it to crash? So, another way to say that is: Does changing the config while its running cause the crash or changing it at all after boot up?
I'm really fishing here - I don't have VSL yet (SOON! SOON!) nor, obviously do I have to code to the performance tool. But if you found a workaround (it sounds like it since you figured out a crash symptom?) then more power to you. If you have any more specifics or if you happen to have pencil and paper around next time you get the bug, post it up and I'll do what I can (which is limited, i'll admit.)
good luck! I wish I could be more help but I'll do what I can.
-denny-
p.s. Are you using any "non-standard" things like virtual midi/audio cables, etc? If you are (or if you're not, as a test) see if you can use different midi devices to route your signal around. It might be that what you're seeing is a bug in the virtual midi driver code, for instance. For instance, if you're using midiyoke or something, maybe it doesn't like being disconnected, but it's the performace tool that's taking the blame.
(Midiyoke in my experience has not been that hot. i think that there are better alternatives.)
-d-