Can't extract par archive

Hi there

I have moved from PAR v. 1.012 to 1.025 when I reinstall a new version of my strawberry perl. I recently used pp for a simple script and the resulting exe was ok. Now I'm trying to reproduce a series of steps to package a gui application, (steps that were working with my old perl install)
One of these step was to unzip the par file produced by a call to pp

pp -v 3 -cd .\ppcache -a glade ... -o %file%.par %inputfile%

but the par par file can not be unzipped using 7z (v. 15.12) or Jar

It can be extracted by Window7 file manager, but I would like to do this in a batch file.

Thanks for any help

François