Jeep - Cherokee :: Power Steering Pump Leaking

I have a 1999 Jeep Grand Cherokee which I bought used. Last oil change they told me that the power steering pump was leaking. The leak was not enough to be seen, but it did seem to make some noise every once in a while so I took it in to get a new power steering pump at the dealer. Two days after they put the new pump in, power steering fluid was pouring out on the driveway, it was a really big puddle of fluid. I had to put new fluid in to drive it five miles back to the dealer. They said that it needed a new line, they were not sure why it needed a new line, they guessed because of the high mileage, 164,000 miles.

I told them that my Mercury has 287,000 miles on it and has never had the power steering pump replaced or the line either. I have driven most every car I ever owned 300,000 miles and have never replaced a power steering pump or line. But anyway, when the Jeep was supposed to be ready, they told me that the new line blew up spraying fluid all over the shop as soon as they started the Jeep and they had to get new parts so it would take another day or two. My question is what caused the new line to blow? My thinking is there must have been something wrong with the new pump or with the installation, somehow it was outputting too much pressure, anything that could blow a new line, would blow the old line.