Whether or not Boards of Canada actually performed at this event is debated. More information can be found on the Spanish forum ClubbingSpain [1][2], where some users assure that they in fact played.
The tracks said to have been played by an attendee are:
"A mixture of different tracks from Music Has the Right to Children ("Roygbiv", "An Eagle in Your Mind", "The Color of the Fire", "Telephasic Workshop", "Turquoise Hexagon Sun", "Aquarius", "Rue the Whirl" ...); from a previous EP (Hi Scores, Seeya Later, Twoism, Sixtyniner ...), and another track whose origin I do not know."