According to a famous Argentine entertainment journalist, Bebe Contepomi, who posted a video on a well-known news channel's blog (called TN), the show taking place on February 26th will not be cancelled.
In the video he says he spoke to a TimeForFun (the guys who are bringing Coldplay to Argentina) representative and told him that they're doing all they can to play in the River Stadium, but that even if they can't, the concert would be made somewhere else, in another venue. It was also confirmed by The Oracle that the show goes ahead as planned:
February 9, 2010 - submitted by Ana, Argentina
Q. Dear Oracle, I come to you today with a matter of life and death (not literally, but it might turn out that way) right now I am freaking out!! I just heard on the news that all shows on the River Plate Stadium are suspended until further notice, what will happen with the Coldplay show on February 26th? Please, don't leave us without the show there has to be something that can be done.
The Oracle replies:
I checked with management as a few fans had heard similar news and was assured that as far as we are aware the show is going ahead as planned.
Pictures of the original Coldplay Parachutes globe by winning auctioneer, NumbersGirl: