It is possible that word is changing the .pz3 extension to .doc or .txt ; make sure that is not the case. Also make sure you are saving as a text file so that Word is not adding hidden formatting codes. You do not mention if you are on PC or Mac, Mac people might correct me on this but if Word is changing the hidden extensions you may have to go into resedit to restore the file type and creator codes.

Dominique Digital Cats Media