Winclone package installers can be run from a netbooted Mac if the neboot's OS has the compression libraries. To locate the files on the admin system where Winclone Pro is installed, open Applications->Utilities->Terminal and enter:
otool -L /Applications/Winclone\ 6.app/Contents/Resources/tools/bin/pigz
The output should be something like:
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 159.1.0)
/usr/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.5)
On the netboot system, look in /usr/lib and add the above files if they are not present already.
Now when restoring an image from a netboot environment, the pigz compression will work when restoring the image.