Copy Poser 6Runtimelibraries!DAZ to Poser 7Runtimelibraries!DAZ (or whatever your Poser folders are called) and try loading again. The only drawback to this is that you need to keep both instances of the !DAZ folder up-to-date if you add new sets that use ExP system (generally that would mean sets of morphs with a large number of morphs, not characters or clothing).