http://co-forum.perfectworld.com/showthread.php?p=2578681#post2578681
Thread about it there too. Same deal for me, minus implying the glitch is intentionally induced. I thought I should put one in the bugs forum though. Simply put, zen cannot be withdrawn from the exchange. It's stuck. You also can't make new offers, or cancel existing ones. All that seems to work is withdrawing questionite you have floating there.