NSLU2 - Disk-2 Led doesn't go on

[Luigi Pirillo <luigi.pirillo@gmail.com>]

I have just installed  Debian distro on my brand new Linksys NSLU2.
Can anyone tell me why the Disk-2 Led doesn't go on when I put an USB 
disk in this port?
And more, why NSLU2 doesn't recognize automatically my USB pen when I 
put it in the same port?

I know, I am novice with Linux :-)

Tranks in advance

Luigi Pirillo