Did you ever change any iTunes settings? If not, iTunes by default saves music from your CDs as MPEG-4 files called AAC. Unfortunately this format is not compatible with the Rio Karma. Also, any music from the iTunes Music Store is also locked to iPods and iTunes only, so it also can't play on the Karma.

To use iTunes to rip your CDs, you will need to first change it to save to MP3 files. Go to the iTunes menu, and select Preferences. Then click on the Advanced option at the top, then Importing. Change Import Using to read "MP3 encoder" and set the quality how you would like. The higher the quality, the more disk space will be used by the files.

Once you change the iTunes setting, I'd recommend ripping your music from CD again for the best quality. However, if you aren't concerned with the possible quality loss, you can instead convert what you already have to MP3. To do this, go to the Edit menu and pick Select All. Then go to the Advanced Menu and select "Convert to MP3".

MP3 files will work with more devices out there, and they are fully compatible with the iPod and iTunes as well. AAC generally is only supported by newer devices on the market.