Troubles with the lame library

When I attempt to export as an mp3, it gives the general pop-up, with the option of locating the library or whatever. I select yes, go into a OS X universal folder, I downloaded, though a series of folders, until I get to a file called "libmp3lame.dylib". I select it, hit Open, and I get an error message saying "could not open mp3 coding library!" WHat am I doing wrong? This is a really stressful problem that I can't solve.