I need to see your crash reports. Run Numerology standalone and use 'Contact Five12' to report a bug -- be sure your email is correct. That should grab them and send them up, if not, I'll email w/ further instructions.
OK, will do that tonight.
Since it did work the very first time after installing the new build, I did wonder if trashing the preferences might work. But alas no. Double-checked that the stand-alone version ran OK and that the AUMX plugin works in Logic – both totally fine. Just Mainstage that causes this problem.