A problem I'm encountering more often than ever lately is improper file heirachy structures in compressed files. Here's an example of the right way to do it:

Runtimelibrariespropsjimmyprops

This is incorrect: jimmychairlibrariespropsjimmyprops

The second compressed file will create a folder Poser will never recognize.

In the past few months I've encountered dozens of this sort of basic error, and I've only given you a very mild example. Now I only rarely encounter a file capable on one click installation, and am forced to decompress into a temporary folder and sort the mess out by hand for manual installation.

This may not be the only cause of the problems you've been having, but I'm sure it isn't helping.