Unable to do menuconfig.

Hi, I am following instruction from this page : http://openbsc.gnumonks.org/trac/wiki/Debian_Getting_Started When I do make menuconfig I get to the point until I have to select the mISDN modules. Firstly, I had to download the 2.6.31.6 kernel which is different as described in the page above. And, secondly, when I do select (based on the best 'guess'), there is no change at all ! I am forced to select 'Exit' - it does not proceed further. Is there anything you would like to suggest ? I am running minimal Ubuntu Linux (https://help.ubuntu.com/community/Installation/MinimalCD) as a guest OS using VirtualBox hosted on Ubuntu 9.10. N.