The fire texture (if moded) is in textures folder, but it it controlled (the fire) by particles.dat (and maybe materials.dat) in library folder.
Can you check RSRD version you are using if it has particles.dat and materials.dat too?
I'm not pretending I know how they (PE4 authors) did the fix, if its simply texture edit or dat file edit, but both files from PE4 and RSRD can be compared to see, and edited to made compatible with both mods.
Take a look here too:
http://www.subsim.com/radioroom/show...&postcount=770
(but, unfortunately, links are down too; but still, at least some info)