Gee, one would thing this song would have a text available online. It has a Wikipedia article, and there's a paper on the song titled "Draumkvedet". From Fragments of a Folk Song to a National Cultural Treasure:
http://www.visearkivet.no/pdf_filer/diverse_artikler/draumkvedet.pdf

There's a master's thesis on it, http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=1847&context=td (Draumkvedet and the Medieval English Dream Vision: A Study of Genre)

But no text, nowhere...