(Dapper) dpkg: error processing mozilla-thunderbird-locale-de

[Duncan Lithgow]

I sometimes write email in german so I've ticked German under 'writing 
aids' in the Language selector. However after updating everything else, 
I had to do an apt-get upgrade and this error was thrown up. Strangely 
the german writing aids seem to be working. Das ist gut, ja?

Here's the error, does anyone understand it?

...
Do you want to continue [Y/n]? y
Setting up mozilla-thunderbird-locale-de (1.0.7-1ubuntu1) ...
Updating mozilla-thunderbird chrome registry...find: 
/usr/lib/mozilla-thunderbird/defaults/profile/extensions/: No such file 
or directory
mv: accessing 
`/var/lib/mozilla-thunderbird/extensions/installed-extensions.txt': Too 
many levels of symbolic links
dpkg: error processing mozilla-thunderbird-locale-de (--configure):
 subprocess post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of language-support-de:
 language-support-de depends on mozilla-thunderbird-locale-de; however:
  Package mozilla-thunderbird-locale-de is not configured yet.
dpkg: error processing language-support-de (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 mozilla-thunderbird-locale-de
 language-support-de
E: Sub-process /usr/bin/dpkg returned an error code (1)
duncan at ubuntu:~$