Php/mysql xml and Google maps

I am following step by step this tutorial 开发者_高级运维http://code.google.com/apis/maps/articles/phpsqlajax.html . I have tried all the 3 ways to output data to an xml file . But i get error "error on line 9 at column 1: internal error" which is the line that php script begins. Connection to database is ok. tables and fields are ok. I tried and copy pasted the exact code from google's tutorial (same values everywhere) to check if there was a problem with my database engine or something and I got an error again this time error on line 10 at column 8: Extra content at the end of the document that is $xmlStr=str_replace('"','"',$xmlStr);

I am running XAMPP 1.7.4 [PHP: 5.3.5]

Did you forget this line?

header("Content-type: text/xml");

How do you call your file? From an url?

Thank you