Unfortunately it didn't help. I got the following:

knoppix@3[knoppix]$ synclient TouchpadOff=1
Can't access shared memory area. SHMConfig disabled?

I looked for SHMConfig and I found that I need following line in XF86Config:

Option "SHMConfig" "on"

The problem is I cannot edit this file in live-cd distribution. Well, I also found some suggestions that

Option "MaxTapTime "0"

in /etc/X11/XF86Config-4 might help, but this is again the same problem.

Any other ideas?

Mihal