Comment 23 for bug 456468

This forum post gives another method for restoring the nm-applet:
http://ubuntuforums.org/showpost.php?p=9236722&postcount=16
This can be used as a workaround until they get it fixed. This method is explained in the file
/usr/share/doc/network-manager/README.Debian. Read that to get an idea of what is actually being done there. This is just an alternate approach to the one as described by miked1981 above.

@Martin Pitt
Can you explain how the update to update-manager would fix this problem with nm-applet.
I use pppoeconf to connect to my ADSL connection. And I lost my panel applet after I configured my ADSL connection (this is also the case with other people on the forum thread I linked above). Before that, on a clean lucid install, the applet was appearing normally and I could connect to my University's wireless networks.
Here's what I get when I type "nm-applet" in the terminal:
** (nm-applet:2271): WARNING **: <WARN> constructor(): Couldn't initialize the D-Bus manager.

And this is what my .xsession-errors has to say:
** (nm-applet:1832): DEBUG: old state indicates that this was not a disconnect 0
** (nm-applet:1832): DEBUG: old state indicates that this was not a disconnect 0

And I got the above outputs when I was not using the workaround described in the thread.