Could be that the following report refers to the same incident:

 http://www.indymedia.ie/newswire.php?story_id=64624

it's about 3 arrests related to a squat.

"Dublin Grassroots Network, which is organising a Mayday weekend of
events for an alternative Europe, today condemned the repression of
activists campaigning against the World Economic Forum in Warsaw.
Poland is one of the ten "accession states" due to join the European
Union this weekend."

 http://www.indymedia.ie/newswire.php?story_id=64622

from a post in irc ireland:

"Three people - two men and a woman - will appear in court in Dublin this morning to face charges under the Public Order Act.
They were arrested in Leeson Place last night on suspicion that they were preparing for a potential disturbance over the May Day weekend.
A number of items, including crash helmets, assorted tools and poster-making equipment were seized."

 http://www.indymedia.ie/newswire.php?story_id=64616