Just to nitpick further, it's actually the ONLY case since the concept was established.

I'm not justifying it, I'm just pointing out that the Popes have traditionally been regarded as wise but still human. Ex Cathedra has only been invoked once since the concept was invented, so it's meant to define religion redefining pronouncements. I'm only clarifying this to alleviate the misconception that "anything" the pope says is automatically viewed by the Catholic Church as 100% Awesome. Full disclosure: I'm an agnostic "recovering" Catholic.

What the pope says is only infallible when he speaks Ex Cathedra. http://en.wikipedia.org/wiki/Papal_infallibility