I have just picked the nb and nn translations of Debian installer in Skolelinux repository and commited them to Debian Installer repository.
As D-I had a few changes since last time the translations were synced, the 1244t0f0u files I grabbed from Skolinux became 1230t11f9u when merged with Debian installer template.pot file.
So, you probably need to pick up nb.po and nn.po again from D-I svn repository and commit them to Skolelinux repository, then complete the work again.
I can't do this because I don't have commit access to Skolelinux repo....