I found a few references to O MIN FLASKAN FRIDA, but no lyrics. One source calls it Danish, another calls it Icelandic.

The following albums contain it:

Schola Cantorum Reykjavicensis, "Two-Part Polyphony," Smekkleysa CD, 2006.        

Marta Guðrún Halldóttir & Orn Magnússon, "Íslenskþjóðlög," Smekkleysa CD 2, 2000.

Various Artists (The Hamrahlid Choir), "Icelandic Folksongs," Hastedt CD 805, 1995.

This information is from Allmusic.com.