FPX files are usually associated with one or more libraries.  When one builds a part or several there are five paths that have to be set right.  One for UserPreferences, one for DefaultPreferences, one for the default fpx file, one for the destination for builds, and one for the destination for step models.  If any of these is not as intended, builds will be wrong or fail outright.  I have lost many hours in the aftermath of these kinds of mistakes.  I'm a newbie.

What if there were a path settings file for a library that listed all these paths, and was loaded once when the user picks a library to work on.  In one dialogue area the user could associate multiple fpx files with one library and its defaults, or multiple libraries and defaults with one fpx file.

Then when you build, your build saves the results using the library defaults to the right place(es) with the right settings.  [This may require iteration to update all the libraries that use that fpx file, each with different preferences.]  This path information could all be a put in a new 'library script file'  that is built using a standard text editor separate from PCB Library Expert.

If paths have to be entered in PCB Library Expert, at least make it possible to type in a path rather than having to follow the file hierarchy down to it. 

Drooling here