Okay.
This isn't working, while MainStage 2.1.3, Logic 9.1.6, Live and every other program I have has no problem.
I've got a clean 64-bit MIDI driver setup, running on an octo Mac Pro, which is running a 64-bit kernel and running OS X 10.7.2. All the latest stuff and up-to-date.
I've spent a day and a half of my time trying to isolate what it might be which is causing this problem - but without knowing from Apple which requirements they've changed since the previous version, and also what in their requirements for MainStage is different than for Logic, I've got nowhere to go.
Seeing as "Bobfrompowell" is also having a problem (although I don't know if it's the same problem, on the surface it manifests itself the same)... I'm not alone in this...
I'm a pretty good reference for MainStage - I've gone out in front of thousands with just controllers, a MBP and everything I can throw at MainStage.
Essentially, I'll continue with v2.1.3, *still* hold off on buying an i7-based MBP until there's a version of MainStage that will work with it.
And, I still consider it really bad from a Customer Sat point of view that the EVB3 sustain pedal fix never came out in a Software Update release, even though Logic got this bug fix months ago. The point of MainStage was to be able to take your Logic instruments and reproduce what you did in Logic *live* in MainStage... If you use the EVB3, it hasn't been that way for months...
If anyone from Apple's MainStage team wishes to contact me directly, I'll be happy to provide details of what's happening here.