"the file isn't in the correct format"

Hi,

I've just opened MainStage 3, and all of my concerts are not loading. Each time I try to load one, I get the same error message.....

I'm running Time Capsule so I'm assuming I can pull a backup from Time Machine.... but I'm wondering how or why this would happen... I recently upgraded to Yosemite 10.10.3... so I really hope it's nothing to do with that?...

I'm also really fortunate, I'm not sitting in front of an audience, about to perform a gig..... this would be a disaster.... and only goes to destroy my confidence in software instruments.....

If anyone has some advice that would save me digging around too much, it would be appreciated...

Mick