They left the rendezvous radar on during the descent, which meant that the computer was getting data from two radars (the landing radar and the rendezvous radar) at once. The computer couldn't handle that much data coming in at the same time.
I think it would be cool to build a mockup of the DSKY, put in some small embedded processor running this software, and use it as a wall clock or something like that. Probably wouldn't take much in terms of processor power.