You don't need WAVs. You just need to correctly link the MP3s.
The "incorrect function" message you are getting is from PowerPoint and Windows
telling you that the function of writing to a CD cannot be done from within
PowerPoint.
When you pack your file, pack it to your hard drive. Pack and Go, PowerPoint
and other applications will not save files to a CD-R. You need to use your CD
burning software for that step because it is designed for that specialized task.
So, first resolve the problem with the music files. Since you inserted them in
the presentation, you must have moved them or renamed them if Pack and Go can't
find them. When you insert a music file in PowerPoint you tell PowerPoint where
the file is and what its name is. You either need to delete them from the
presentation and reinsert them correctly or make sure they are where you
originally told PowerPoint they were and that they have the name you told
PowerPoint. If you do the latter, test the presentation by playing it to make
sure that PowerPoint can find the music files and play them.
Then, pack your presentation to a folder on your hard drive. Pack and Go will
create two files. One is the packed presentation (PRES0.PPZ) and the other file
(PNGSETUP.EXE) is what you run to *unpack* the file. Run PNGSETUP.EXE and all
of your files (your presentation and your sound files) will be unpacked.
Now, open your CD burning software. Put a blank CD in your burner. Move the
unpacked files to the CD. Click on the "Burn" button.