I’m writing server-side programs in PHP for an iPhone app. And I have no iPhone. 😛
The iPhone app requests XML files from the site whenever a user runs the iPhone app. You may visit http://www.appvee.com/iphone/ads or http://www.appvee.com/iphone/latest for the XML files.
And a message box will show up with the following error messages: ‘Web Site Error Conversion of data failed. The file is not UTF-8, or in the encoding specified in XML header if XML. ‘ 
Maybe I must add header(‘Content-type: text/xml’); at the beginning of the PHP files? I didn’t add this line and it worked well before.
Any help is greatly appreciated.
I agree with ceejayoz, looks like this is a special characters issue.
I would suggest using the htmlentities method to encode the data in the xml file.