Here is the instructions from the readme. I managed to convert some files the last time I used it:

Quote - 1. Power up Mover

2. Click on the 'Decode' radio button (the little round thingie). The
   blue arrows should appear indicating that you are going to translate
   from a difference file (pcf) to a figure file (obj).

3. Click on the 'Difference File' button. An 'Open' dialogue should
   appear.

4. Use the open dialogue to navigate to wherever you've put the pcf
   file. Hint: It's best to put the pcf file wherever you want the obj file
   that you're creating to be. This will usually be ......Poser3RuntimeG
   eometries*** where *** is usually specified by the person who created
   the pcf file (look for his readme).

5. If step 4 went OK then you should find that the file name has
   appeared in the box to the left of the 'Difference File' button and a
   filename has also appeared in the topmost box - 'Original seed File'.

6. The 'Original Seed File' box is telling you the name of the file that
   was originally used as part of the process of creating the pcf file.
   However, Mover doesn't know at this point where that file is on you
   computer or even if it's there at all so you've gotta go find it. Click
   on the 'Seed File' button and another 'Open' dialogue appears. Navigate
   around until you find the seed file. This will usually be in ....Poser3
   RuntimeGeometriesxxx but xxx will vary depending upon the particular
   seed file. It's probably best to use the Windows find file facility to
   track it down.

7. If you've found the location of the seed file and clicked 'open' in
   the 'Open' dialogue then the seedfile name (and full path) should appear
   in the seed file box. The 'Convert' button will also be enabled now.

8. Click on the 'Convert' button.

9. If you've got the right file names then a message will appear that
   the conversion is complete (and it will beep). If not, you'll get an
   error message. I'll assume you got it right rather than going through
   every possible error.

You can now close down Mover and if you use windows explorer (or
whatever) you'll find that you now have an obj file in the same
directory as the pcf file and with the same name.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi