For some reason this file apparently disappeared from IMSLP.
According to the WIMA->IMSLP transfer log there should exist a file, http://imslp.org/wiki/Special:ReverseLookup/115565
I've re-uploaded the score and recreated a work page.
I am aware of the potential copyright issues with that score. I asked Rzewski about this back in August. Here is an excerpt from his reply:
I don't have any permission from anybody for these things, except for "Triumph of Death", which was originally written as music for a theatrical production of Peter Weiss' play "L'Investigation" ("Die Ermittlung"), for which permission was granted at the time (1988).