This has to do with a change they made in the way the Pro Pack reads geometries (their gonna change it back with the next patch).

Open the PZ3 in a text editor. Your going to find that the geometry of some of your props and other things have been embedded into the PZ3 file (it doesn't reference the original .obj anymore). These geometries are seperated into groups by lines that start with the letter 'g'. Generally group labels look like this: 'g lForeArm', 'g hip', 'g rFoot', etc. Sometimes you will find (generally if the grouping tool has been used) group lables that are just a 'g' with no name after it. Poser could read these empty 'g' lines fine, but this is where Poser Pro Pack screws up and doesn't read any of the 'f' lines (faces) that fall under that empty lable.

Okay, enough theory. Here's how you fix it:
With your PZ3 open in a text editor do a search for 'g'. Whenever you find one of these un-labled g lines, give it a lable. It can be anything... 'g blah', 'g blank', 'g unknown', whatever. SAVE AS the file (just to be safe) and you should be able to open it up in Poser Pro with no holes.

Hope this helps.