Here's the AP report:
http://abcnews.go.com/International/wireStory?id=2149269&CMP=OTC-RSSFeeds0312
Artesanraju is the peak from the Paramount Pictures logo. The [edit]south-east[/edit] face is popular. Brad Johnson's "Classic climbs of the Cordillera Blanca" lists three or four routes for the mountain, I think.
The AP report mentions that they were climbing without a guide. Starting this year Peru said they would require all visitors to the Blanca to hire a guide. This struck me as mostly a way to help the local economy. Not too sure if...
a) You had to hire a climbing guide who would climb with you, something these folks did not do.
b) You had to hire "someone," who at the very least would sit at your campsite while you climbed and watch your stuff. Which these folks either did, or did not, do.
c) The rules are laxly enforced, big surprise for Peru, and these folks just ignored them.
Without knowing anything about the accident, the climber's level of experience, or anything else, I have no idea what effect their choice not to hire a guide had on the accident.