I'm using Audacity 1.3.13 beta (unicode), which can't be much different from the one you've got. If you click Libraries on the L/H side of Audacity Preferences, what do you get? On mine, there is a button for "Mp3 Library, Locate...." to click. If you have saved the previously downloaded Lame_enc.dll on your computer, you can find it from there. Otherwise, try clicking the DOWNLOAD button next to where it says "Lame Mp3 Library" (which I haven't done before). Maybe you can download a version of that Lame library which will be compatible to your version of Audacity. Good luck.... :)