There seems to be no translation for swedish.
I created one pretty quick and uploaded it here if anyone else need it: https://gist.github.com/2413101
It contains some directly translated swedish sentences, but you are welcome to update the gist if you want.
I just installed Relate 2.1 demo site and the English translation works but not the Swedish.
When i look at the lang folder i can see the following files with content:
Also there are no errors in the installation log. Does the demo site come without complete translation for swedish?