Newbe question can`t render mp3

Hi, m a newbe in this forum. I tied to render a project in mp3 and followed the steps of the manual. Once I hit render it says ERROR: I NEED LAME_ENC.DLL TO ENCODE MP3. Tried to render to wav and it worked fine. What do I do wrong or what do I have to do to be able to render to mp3? Please help.

You Need this : Just drop that into your main Reaper Folder and you should be set. ~Rob.

THX man. That was a quick solid answer now it is workin!!!!!!!!!!!!!!!!!!!!