[Bio-Linux] chown problems?

[Jose A. Andres]

Hi All!

I've decided to mount an external hard drive on our bio-linux machine so
everyone can store there their raw data (mostly traces)

I already done that (/media/usbdrive)  the /etc/fstab line looks like

/dev/sdd1       /media/usbdrive auto    rw,user,auto     0      0

There only one partition of the drive and on it I made a data-storage
directory with 5 different subdirectories for the users...

(ls -l on /media/usbdrive/data-storage/
total 160
drwxr-xr-x  3 manager manager 32768 2006-05-09 16:19 user1
drwxr-xr-x  2 manager manager 32768 2006-05-09 16:18 user2
drwxr-xr-x  2 manager manager 32768 2006-05-09 16:18 user3
drwxr-xr-x  2 manager manager 32768 2006-05-09 16:18 user4
drwxr-xr-x  2 manager manager 32768 2006-05-09 16:18 user5

As you see manager is both the owner and the group. I 've tried to change
this  (log as manager) using Konkeror and sudo chown
e.g. sudo chown user1 /media/usbdrive/data-storage/user1

but I got the following error
chown: changing ownership of `/media/usbdrive/data-storage/user1':
Operation not permitted

That's also true even if I log on as root!!

Any ideas on how to change the onwership of the files?

Thanks!

/Jose