From what I've gathered from reading the various bits of stuff on this, the issue more or less revolves around making changes to the progam's *.ini file -- which ZEW 3D and Renderosity contend is a violation of the terms of the EULA and which spothmann contends is not the case.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)