I'm running Poser 4 (not Propack) under Classic mode of OSX 10.1.5 and it works just fine, with Millennium people also. I have just noted two small problems: doubleclicking a pz3-file won't load it into Poser, and if I quit Poser and want to start it again I have to force quit Classic mode first. My machine has rather much RAM: 768 MB.