mitchellhu

I have this kind error also, JSONParseError: Unexepected < Found, almost like yours.
After debugging this error, I found '<' is send by php.
Because Adobe Dreamweaver always generates a lot fixed php code before section. Those codes brings trouble to flex JSON module. Make your php code pure as <? ?> section only, would gives a good answer for this tutorials.

Actually, it took me 3 days for solve this error.
Flex is very new to me and my English ability is poor.
Hope this answer could help you.