I had a similar problem after installing Poser 7 and Poser 6 at the same time. The morphs would work fine with Poser 6, but with Poser 7 (AND pointing to the Poser 6 Runtime) it wouldn't work. After some feedback from someone else, and some digging of my own, I realized that if the injections make use of a Python script, and those injections are not in the default runtime directory, the Python scripts don't get called -- a problem since they probably all use relative paths.

So I had two options:

1. install the content again into the Poser 7 Runtime (easiest)
2. find the pz2 file, potentially in the Pose directory, that has the relative path (the line is probably  "runPythonScript "), and then change it to the full path (harder)

This may, or may not help you, but this is the problem I ran into. It could also just be that the file with the character in it is somehow corrupt, and you just need to make a new scene, or the content just needs to be reinstalled, or both.