I think it's RDDesert, I saw some issues with it. Not sure, but I think.
Trainer is ok. Other mods shouldn't conflict if they are installed correctly.
The ENB should be ok too, but try it last to be sure.
Now, the best thing to do, even if it takes time, is to put mods one by one, and test, if one of them is conflicting, you'll know which one.
Don't forget to backup your clean GTA IV !
edit : I lol'd with Samuel L. Jackson, love this guy ^^