cristian on "body.xml:1: parser error : ParsePI: PI xmlversion space expected"

Hi! Somebody knows how to solve this?
body.xml:1: parser warning : xmlParsePITarget: invalid name prefix 'xml'
<?xmlversion="1.0"?><methodCall><methodName>pingback.ping</methodName><params><p
^
body.xml:1: parser error : ParsePI: PI xmlversion space expected
<?xmlversion="1.0"?><methodCall><methodName>pingback.ping</methodName><params><p
^
body.xml:1: parser warning : xmlParsePITarget: invalid name prefix 'xml'
<?xmlversion="1.0"?><methodCall><methodName>pingback.ping</methodName><params><p
^
body.xml:1: parser error : ParsePI: PI xmlversion space expected
<?xmlversion="1.0"?><methodCall><methodName>pingback.ping</methodName><params><p

CentOS, Apache, Wordpress 3.9.1.