Actually, you need the retail version of either Eazy CD Creator 4 or 5 to have built in "ripping" capability.
Are you trying to create audio cd's to be played on a standard audio CD player?
Is so, then you do need to convert the MP3s to wav files using audio "ripping" software.
There are numerous freeware, shareware, and commercial packages out there. Just go to your favorite software download site, or computer store, and get the package that best fits your needs.
If you are trying to copy the files to CD for storage, backup, or to transport them. You need to be in a data and not a music CD session.
If you are going to use the CDs on a portable MP3 player. I would check the player documentation for required format. You may be able to just copy the MP3 files onto a data CD.
Chas