how to temporarily use version available for FF4 Waardering 1 van 5 sterren

I'm a noob and I need explicit instructions on how to do the modifications recommended by this poster. It sounds promising, as mpc 0.9.4 does not function for me in FF 4.01. Thanks in advance for any and all help.

Deze beoordeling betreft een eerdere versie van de add-on (0.9.3).