You're both pretty much correct, Erik and spaffe.
Nattestid Ser Porten Vid can have two meanings, I think, and I reckon both Erik's and spaffe's translations are good. It's quite a poetic title, where "Nattestid" means "The time of night", more or less. "Ser" is "looks" or "beholds". "Porten vid" = The wide open gate, the wide gate.
Hordaland Doedskvad - Spaffe's explanation of kvad is pretty much spot on. Hordaland is the region/county (Norway are divided into 19 different regions/"fylker") in which Bjoergvin (today called Bergen) lies. Bjoergvin is Høst's hometown.
Over Bjoergvin Graater Himmerik - Himmerik is a difficult word to translate. Himmel is the standard Norwegian word for heaven, but himmerik is a more poetic and romantic version. "Rik" comes from the word "rike", which is closely related to realm or kingdom. My translation would be something like "The Heaven Cries Over Bjoergvin" or "The Heavenrealms/spheres Cry Above Bjoergvin".