The caller later admitted that the whole thing was a prank, although there are people who say that the man who retracted the statement did not sound like the original caller.
"Faaip de Ioiad" (note that the last word is not spelled "Oiad" as the track title) means "Voices of Your God" in Enochian Magic. This information comes from the alt.music.tool newsgroup and a post by Steve Sobel.