I talked to Kurosh and apparently those masts were older Gaastra masts. One was one of the original black Gaastra masts (3 years old) and the others from 2006. I don't think you can complain about a 3 year old mast breaking - that's a good shelf life for a carbon product being used as much as Kurosh sails.
Incidently, I had some problems (as did others) with the Gaastra masts earlier this season, but Gaastra have stepped up to the plate and released a better mast. 300-400g heavier and a different finish; haven't broken one since and I sail everyday. The new Gaastra masts are completely gold with thin black stripes the length of the mast if you are trying to work out which is which...
I wouldn't be suprised if a lot of masts breaking in Brazil were due to improper care. So many people leave sails fully tensioned in the sun in Europe, which is fine I guess, as the earth is a lot further from the sun in Summer (June-Aug) but when you feel the full force of our Southern Hemisphere summer (Dec-Feb) you will see masts break. We are used to it here in Australia so we usually only rig a few minutes before we sail and dip the masts in water to cool them. I'm sure having masts banged around on the airplane doesn't help either, so there's usually more mast breakage at an event everyone has flown to than just the local comps.
I think its ok to pick the masts that are breaking less from watching the pro's. Hey, they sail more than everyone else and chew through a lot of gear, so if the guy you are watching isn't breaking his brand of masts than they are probably a great mast.
Until some brands start making masts 500g heavier and use double-bias carbon; every brand is going to break masts. Its the same with booms. There are some very simple ways a lot of the gear on the market could be improved structurally, but I'm sure that's more complicated commercially than me just putting this on a forum. I'm sure people don't want their gear 50% more expensive :-/