Comment 7 for bug 228032

Sadly, I don't think you can reproduce it, unless you work in France/are a french citizen.

You need to go to impots.gouv.fr, and have already created a ssl certificate to identify yourself.
Then go to https://cfspart.impots.gouv.fr/tdir-03/accueil.html
It will check the dependencies to the process (browser, OS, java vm).
For Hardy, it will warn because FF3 isn't in the list of supported browser (firefox-2 is), but you can still continue (that's just a warning).
Then you proceed filling up some forms, and at the end you have to sign your declaration.
Since there are no cross-plateform API to use the certificate stored in the browser, the developpers at impots.gouv.fr have
built a binary (probably a different one under each OS/browser) to access the certificate store and sign the declaration.
So the java applet download a .so for the signature(the libjsec.so), but sadly this dynamic library can't be used because of the linkerror.

As you can see from this search (sorry, in french) there's quite a lot of people who had some problem with this:
http://www.google.com/search?hl=fr&q=ubuntu+impots.gouv.fr+signature&btnG=Rechercher&lr=

Note: using firefox-2 isn't a suitable workaround, since the java installation is (was?) quite broken when I tried.