Hi all future diggers,
This lines to keep trail of my findings....
"Guest Additions" do not install correctly with Windows has host and knoppix has guest....
proceed like this...
Under windows, double-click on the downloded file for "Guest Additions"
start the Knoppix VM
Start a "file manager"
Open the CD/DVD drive (which contains a cd image of Guest Additions)
Get supervisor priviledge
execute the *.sh file to recompile the Guest Additions
that's all folks...
Hope it may help as I found for some other topics
Kaiser Sauzet