Sorry, unfortunately, I've since uninstalled and reinstalled Poser 5 (which for now seems to have corrected the problem).  If it helps, I'll give you a detailed description of the two folders:

The first folder which contained the converted MC6 files to MAT Pose contained 47 converted textures in them.  This folder displayed in my Pose library, however, upon opening it, only 1 out of the 47 files would show up in the display, and that file was the one used to remove all textures from the model.  

The other folder which contained only 3 files, used for applying different poses to M3, did not show up at all in the Pose library.  

I had checked all the extensions and they were all correct (all had .pz2 with corresponding .png).
I physically checked all the folders to make sure that they were actually there, and they were.
I had loaded these same folders/files into my son's laptop and it loaded fine without a problem.

So the only conclusion I can come up with so far is that there may have been some corrupted files in that particular Poser 5.  

In any event, I appreciate your feedback and willingness to try and resolve this.  :)

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