Of course there is always a chance of failure. The space shuttle blew up, too. And it was not that old...
I heard of the accident on the tourist line now and then and pieced some of it together. Please can anybody tell me some details? AFAIR rules were violated. The result was that boiler inspection and "safety" is more restrictive in the States now. Unfortunately more rules won't help imho. They, too, can be violated. From what I have seen and experienced many rules date back to the times when the engines were operated on a regular basis and used in much tougher duties. So even with increased age these rules provide quite ample reserves for today's runs. Worry? No. Respect? Yes.