During xml pharsing, I met the error that is caused by some character. I selected the character's code by this query script
SELECT UNICODE(' ') AS C1, UNICODE(' ') AS C2, UNICODE('?') AS C3
The character looks like blank but code is 63.(63 is question mark) The character might be changed to normal blank character by paste to web control. So, look this link. Code 63 Blank Character