Okay, here's a screenshot from Daz Studio 4.0 Pro ... it seems to be working okay for me.  Are you using Windows 7?  

In the past, Windows 7 has messed me up when I'm trying to replace files in Poser ... for some reason it caches the old files and won't replace them with new ones, it will pull the cached files, even if you've deleted them.  I wanted to pull my hair out one day, until someone showed me what it was doing.