Yeah, and Serato have a list of known issues when running Scratch Live under Mac OS X Lion - so for most people it would be best to wait until they are resolved. As far as this issue goes, I believe that it has been fixed, though it will have to undergo testing before it is released (and allow for any further issues to be found). We've had beta testers using MixEmergency with Lion for some time now, and this is the only issue found so far.