PHP Webdav/ Exchange question

I have been working on a php application interfacing with exchange, my
application works with PROPFIND but when I do a search I get an error
400, can anyone point out to me why, I do a METHOD SEARCH, my code
is below:

My query is well formed and works, so my header request may be
incorrect?

HTTP_REQUEST_METHOD_SEARCH=SEARCH

$req = &new HTTP_Request($url);

if (is_string($username)) {
$req->setBasicAuth($username, @$password);
}
if ($method!=HTTP_REQUEST_METHOD_SEARCH)
{
$req->setMethod($method);
$req->addHeader("Depth", "1");
$req->addHeader("Translate", "f");
}
else
{
$req->setMethod($method);
// $req->addHeader("Depth", "1");
// $req->addHeader("Translate", "f");

}

$req->addHeader("Content-Type", "text/xml");
$req->addRawPostData($query);

$req->sendRequest();
if (PEAR::isError($req->sendRequest())) {
echo "ERROR:".$req->getMessage();
}
$responsecode=$req->getResponseCode();