KDE does not default to a translated setup... it defaults to English, even though the system uses another language. The setup dialogs which configured themes and language were ripped out, but KDE wasn't fixed to default to the system locale...
OK, this is a bug for Norwegian only - KDE has named this locale "nb". All other programs use "no", and this is what anaconda writes out as well.
yes, KDE has named this locale "nb". KDE should use standard locale name.
it's fixed in kdelibs-3.1-6