It looks like they found a large crack in the foam that covers a bracket that connects the liquid oxygen feed-line to shuttle Discovery's external fuel tank. It also looks like the shuttle program isn't catching any breaks. Still, I'd rather have them find this on the ground then have another Challenger or Columbia incident.
Something has to give when extreme cold meets extreme heat (I think the temperature was in the 90's). I worry this will be used as another nail in the coffin of manned space exploration.