AJR 15 Chirping 3 times

[adelara]

No freaking clue why.. this seems to happen at random: I hear
it chirping 3 times     then plays ok for a while... I mean, it is
always playing ok, but that chirping is annoying.
Messing up with the navigation menus, i.e. going from
one directory/cd/group to another sometimes causes the chirp
to happen again, but it's mostly random.
The chirping does not come through the headphones, so people
around can hear it loud and clear....
The batteries were replaced too.
Question are...
- is this a hardware problem ?
- is this a HD problem ?
- is this any know software problem ?
Thanks,
-Alex