I have both Nero 5 and EasyCD Creator 5 running on the same machine. I know there was a problem with the EasyCD Creator software, it disables some of the registry entries that are necessary for ROM devices, but there is a string fix for that somewhere. Perhaps you thought Nero didn't work because of the problem with EasyCD Creator. Never heard of that conflict before.
What type of image files does Nero use again? They're *.img files right? Might have some luck getting converters from ISO to IMG, I'm not totally sure though 🙂.