right now it seems to me that the printer drivers are almost completely missing...

On my "good old" machine there are loads of gzipped .ppd driver files in some subdirectories of
/usr/share/cups/model/gutenprint

But on the Knoppix 5 machine there are NONE in this subdirectories... I dont know too much about cups - but this looks like tere is something essential missing in cups and/or gutenprint
Until now, no (apt-get-) installation-try has fixed this problem for me...