you need to replace your folder PRG_ENG should be called like that.
basically, everything you need as far as I understand, is to replace your Engrel.exe file (make sure to have backup files)
but to be honest, horn of Ugrok is very tricky item - mainly because it bugs game very much. I expereinced tonns of disconenctions due of it usage. So in our network battles we almsot never use it.
i played only 3 battles on new random map, and maps was good, except "road to kislev". too unbalanced i think and lots possible places for bugs.
but its OKish
what i hated, i really hated, is that frigging conenction. i really angry about that stupid DO engine so each other game gets kicked out. also i dont like when Jero and Ramiro play at same PC. it double up tournament time. wtffffff pls dont do it! its unethitcal for other players imo.. (well i missed 40 minutes of tourney, im unethical too)
all in all i would be very happy if it would be possible to move DO engine to some other platofmr, a least fix that anoying network code..