Please help ASAP! CD burner question!

I have a question that needs help ASAP. My friend has a burner in her computer, and she has downloaded a program called zy2000 that lets you turn mp3 files into WAV files and burn them onto CD. It works fine with her files (mostly taken from but when we try and do it with mp3’s saved on a disk the program will not take them. Why is this? They are the exact same files; we have even transferred them from disk onto her hard drive and they still won’t work. It’s like the computer knows that they are from another source and so won’t take them. Is there ANY way to make this work? It’s very important since this has to be done within the next day!!! Please help!!!