Disc II: CD Change Problem

I once had a problem with my CD Changer. It says CD ERROR on the lcd display and then when i try to eject the changer, it won't, then the display will say NO MAG. I was able to fix it before by tinkering with the eject button and the magazine. I forgot what i did EXACTLY. Now i'm having the same problem again. Does anyone have specific instructions on how to fix this?