Funny I just had the same problem the other day (see "Please Help: Can't use Vicky 2 and Michael 2 together" thread from yesterday) using Vicky 2 and Michael 2 together. The problem is that these figures share the same names for the full body morphs and Poser apparently can't keep track which figure you're modifying. The answer is to use the EMC Fixer null figure from Nerd (see the thread mentioned above for the link).