OK, I am at it again! Still no luck installing the wireless driver with ndiswrapper but maybe I am getting closer (I hope!). Last time when I tried to install,I got this message (this was with the Suse live DVD,but it should be similar with Knoppix)

linux:/home/linux/ndiswrapper-1.37 # make
make -C driver
make[1]: Entering directory `/home/linux/ndiswrapper-1.37/driver'
Can't find kernel build files in /lib/modules/2.6.18.2-34-default/build;
give the path to kernel build directory with
KBUILD=<path> argument to make
make[1]: *** [prereq_check] Error 1
make[1]: Leaving directory `/home/linux/ndiswrapper-1.37/driver'
make: *** [all] Error 2

Where is the Kernel build directory and how do I get it to build those files?
Any suggestions?
As for knoppix I am still trying but for now I always get the same (discouraging) answer: bcmwl5.inf :invalid driver