I get the same problem. MMV will run on my XP laptop, but not on my studio 98SE system. I get a 'missing instrument .dll' error. I have re-installed twice, installed then re-installed the upgrade to 1.1, and checked that the .dll file is copied to both driver and vst folders. It still doesn't work.
Arturia techies - if you read this, please sort out a fix.