That wasn't even a year before I was back on track and had this sorted.
The trick was to follow the hints from
http://www.minimig.net/viewtopic.php?f=4&t=275&start=10 - which basically installs a different root extender file that now accepts my own untouched build. I even downloaded v13 of Quartus today and it is now playing a silent game of IK+ on the screen to the right of me.
Lubberly!
Though the gfx in the IK+ trainer by Alpha Flight had some odd extra bars at the end of the characters in the scroller...
(Perhaps that is fixed in a more recent version of the source? C-One is based on the 2009 version anyway.)
Time to find those pc speakers, or perhaps my old amp and proper speakers.