Blogger API, insert post issue

Hi there, i am trying to submit a post via blogger's atom api but i do
not succeed. The authentification process works well, so the curl
process works well too, but the problem seems to be with the XML
entry.
Here it is:
$entry="<?xml version='1.0' encoding='utf-8'?>
<entry xmlns='http://www.w3.org/2005/Atom'>
<author>
<name>Clapon Cosmin</name>
<email>cosminx2...@gmail.com</email>
</author>
<title type='text'>Entry 1</title>
<content type='text'>This is my entry</content>
</entry>";

=====================================================
The RESPONSE is :
The processing instruction target matching "[xX][mM][lL]" is not
allowed.
=====================================================
I tried a lot of xml parts found on other websites but i got problems
as well.

Does anyone know how could i fix it? i really need to insert posts to
Blogger from an external command.

PS: i'm working with PHP

It sounds like it's choking on the <?xml ?> line at the start of the entry - try removing that.