Although I know nothing about mandrake your problem does sound familiar.
I was trying to print (via CUPS) from my distro to a shared XP machine, I could get it to spit out a text message by entering
echo "test" | smbclient //jintana/hpLaserJ -P -N -c 'print -'
obviously the jintana and hpLaserJ parts are specific to my LAN
but it just wouldn't print until I configured CUPS to print to something like
the admin:@ was the crucial part although any name would work.
Are you configuring CUPS from some GUI "Printers" command or via "http://localhost:631" in a browser?
I am not at work now, so I can't see the exact settings I have, please post back if this works or not