Default Can't define mp3 ringtone and alarm clock

Hey All,

I am a proud owner of nexus 4.
I use the stock android 4.4.2 KitKat.

I've put a mp3 file on my phone
and I want to use it for two purposes:

1) User the original Alarm clock when pressing on the clock.
2) Set a mp3 ringtone.

On both cases I receive the same message:
"wrong file type, please select again"

Please advise,

Thanks in advance!