Comment 3 for bug 335507

From our additional discussion on IRC #ubuntu+1 here's some further information.

When src/netspeed.c::update_applet() is called (controlled by the gconf refresh_time setting) it calls src/backend.c::get_device_info(). This in turn calls:

 glibtop_get_netload(&netload, device);

to obtain the information for "device" (e.g. eth0, wlan0, etc.).

There was a recent (17 Feb 2009) upstream update (bug #330571) to the package:

libgtop2 (2.25.91-0ubuntu1)

This might be the cause.