MainStage says no midi input but works fine

Hi just started working with MainStage. fine program, but I'm encountering some bugs. sometimes I get a pop up saying 'no midi input available' . but everything works just fine, the patches play, and I can see midi activity in the little screen in the middle above. Wonder what could be the case...anybody any ideas?

also, MainStage crashed on me twice. The first time I had to choose to undo the multiprocessor support in NI Konkat, but after that , it crashed on me again. I'm a little worried since I want to use it live in one week. Any suggestions what might be the case?

ty