I am trying to mirror certain pdf files from a site where the file names remain
the same but one element of the path changes regularly (CMS perhaps?).

A typical file name is of the form

<fixed element of path>/<variable element of path>/$FILE/fred.pdf

If I put in the full path, WinHTTrack Website Copier 3.41-2
happily gets the file for me.  Next week (when I am looking for any changes)
the variable element of the path has changed.

I have tried <fixed element of path>/*/$FILE/fred.pdf without success, getting
error messages like

"Warning:  link is probably looping, type unknown, aborting: ..."

I should add that the way in via browser is via a download page, which
contains a gif image of the PDF icon which, when clicked, downloads the file. 


Grateful for any advice.