I tried your solution of updating the ftdi driver on my Ubuntu 10.10 because if I want to type something in minicom, it does not work (thus it does not get sent to the GuruPlug it seems like). I cann see the boot messages, but not input is working.
I used your HowTo and I was stuck with
because install-sh was not available.
autoreconf -f -i -Wall,no-obsolete
solved the problem and I was able to continue with make
One question that I have: do I have to execute modprobe every time I restart my Ubuntu or does one modprobe adds the module to the kernel forever?