Mainstage 3- No Midi Input

Hi There,

i'm using Mainstage 3 on osx 10.9. I'm having issues as mainstage doesn't seem to recognise any midi input from any source. Or rather, it recognises the devices but does not recieve messages. I've been using a simple plug-and-play USB to MIDI cable which has worked fine up until now in whatever controller I lug it into. When I unplug the cable (plugged in to any controller) I recieve the message 'midi input no longer available', so clearly it recognises the device but fails to recieve any messages. I tried installing the drivers for a freind's controller and connecting via USB to USB, and while mainstage recognised the device for around a minute it's now no longer recieving any messages.

I'm a bit of a novice to this and am meant to be playing a gig this coming sunday with this rig. I am understandably stressed any any help would be greatly appreciated.

Many Thanks,

Matt