Flute ! Ubuntu est contrariant

Voila, ce que j'ai fait maintenant :
> sudo apt-get install libkrb53

Resultat :

Package libkrb53 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
krb5-pkinit libkrb5support0 libkrb5-3 libk5crypto3 libgssapi-krb5-2
E: Package libkrb53 has no installation candidate

Donc j'ai passé :
> sudo aipt-get install krb5-pkinit libkrb5support0 libkrb5-3 libk5crypto3 libgssapi-krb5-2

Résultat :
> rb5-3 libk5crypto3 libgssapi-krb5-2
Reading package lists... Done
Building dependency tree
Reading state information... Done
krb5-pkinit is already the newest version.
libkrb5support0 is already the newest version.
libkrb5-3 is already the newest version.
libk5crypto3 is already the newest version.
libgssapi-krb5-2 is already the newest version.
The following packages were automatically installed and are no longer required:
gconf2-common libwxbase2.8-0 pgagent iso-codes libgconf2-4 libwxgtk2.8-0
libidl0 pgadmin3-data libgstreamer-plugins-base0.10-0 liborbit2 libglu1-mesa
libgstreamer0.10-0
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Cela me semblait positif, j'ai donc repassé cela :
> sudo apt-get install libkrb53

Mais il me remet l'erreur suivante :
> Package libkrb53 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
krb5-pkinit libkrb5support0 libkrb5-3 libk5crypto3 libgssapi-krb5-2
E: Package libkrb53 has no installation candidate

Sniff ! Ca ne marche toujours pas. Mais c'est quand même bizarre cette erreur