This seems to happen when I open up the Hiergamenon entries for various techs and click on the items the technology allows: When I do so, one of the item entries for that tech (I think always the first one?) disappears.  If I do this another two or three times, I get a CTD.  If I had to guess, I'd speculate this is an incorrectly incremented/decremented index into a list or something.  The debug info is at http://dl.dropbox.com/u/8683962/Elemental1_09n-2010-11-20T19-59-12-412.zip