Why we need to retire the shuttle

Over on Space.com, there is an article about some issues around the next shuttle launch. It was all interesting, but there was one line that stood out with neon signs for me.

NASA would avoid flying during the New Year’s holiday because the shuttle’s computers are not designed to handle the year-end rollover.

WTF? Shuttle Y2K? My calculator has a calendar that DOESN’T have a problem with the year-end rollover.