I was trying to access my friend's profile by "http://tw.battle.net/api/d3/profile/灰原愛貓-3465/", I got '{"code": "OOPS","reason": "There was a problem processing the request."}'.
I tried to encode her tag to "http://us.battle.net/api/d3/profile/%E7%81%B0%E5%8E%9F%E6%84%9B%E8%B2%93-3465/", same error returned.