I'm having trouble initialising the ESSID of my wireless
networkcard. If I change the ESSID in my router to
"linux-wlan" everything works. So I can get it to work but
I want a different ESSID.

I set the ESSID with the program (MENU->KNOPPIX->Network/Internet->Wavelan configuration)
It initializes a file called '/etc/pcmcia/wireless.opts'
This file is interpreted by the program /etc/pcmcia/wireless.
I managed to track down the command that is executed and
tried it on the command line with the following result :

Code:
SH > iwconfig wlan0 essid hallo
Error for wireless request "Set ESSID" (8B1A) :
SET failed on device wlan0; Function not implemented.
I noticed a Warning when executing iwconfig :
Code:
SH > iwconfig
...
Warning: Driver for device wlan0 has been compiled with version 14
of Wireless extension, while this program is using version 15.
Some things might be broken...
...
Is there something broken ?