xfce4-diskperf-plugin does not work on Debian Etch

[ar <arichy@gmx.de>]

Hi,

I just installed Debian Etch with Debian Installer RC2 on AMD64 with
Xfce (4.3.99.2).

(http://cdimage.debian.org/cdimage/etch_di_rc2/amd64/iso-cd/debian-testing-amd64-xfce-CD-1.iso)

xfce4-diskperf-plugin 2.0-2 is already included in that installation.

I have two SATA drives connected to my nVidia main board.

They are /dev/sda and /dev/sdb and work fine.

But when I add "Disk performance monitor" to xfce bar and
enter /dev/sda as device, the performance of that drive is not shown. 

And when I log out of xfce and then log in, the "Disk performance
monitor" item is not in the xfce bar anymore.

What could be the problem?

Thanks,

Arichy