You will have to provide a lot more detail if you want a meaningfull answer. The exact error message, Max version, system and OS information at the very least. Screenshots of your render setup dialog, info on the which materials you're using will also help.
And no, downloadloding dlls from unknown sources is not something you should even consider. Almost certainly unnecessary and likely very dangerous.
Max 2016 (SP1/EXT1)
Win7Pro x64 (SP1). i5-3570K @ 4.4GHz, 8Gb Ram, DX11.
nVidia GTX760 (2GB) (Driver 430.86).