Flex : error while connecting to database with XML

Question

Hello,

i'm new to flex, and i've an exam on it next week. I'm following how to build an application in 1 day tutorial from adobe.

I'm stuck on how to recieve data from database.

First, i choose to use AMF to connect with data :

• my PHP class to access my database doesn't work (got an error like: is zend correctly installed,include .... cannot find.....).
• I generate an automatic class : problem i don't understand anything with mysqli

Solution, one user here told me to use a php file which echo the XML to read data

I mean how can you modify the database using XML ? I can barely recieve information using XML :D

Thank you very much