Getting "Invalid request URI" , When trying edit spreadsheet using php

[Thimuth]

I'm trying to edit a google spreadsheet using the following php code.  But 
it gives me HTTP 400 error. Can anybody figure out what's the error here or 
anybody have a better way to do this ?

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// construct the headers with the pre-acquired google auth token
$headers = array(
        "Content-Type: application/atom+xml",
        "Authorization: GoogleLogin auth=" . $this->token,
        "GData-Version: 3.0",
        
    );


$fields = '<entry xmlns="http://www.w3.org/2005/Atom"; 
gd:etag=\'"QQFEF1sdUyt7ImA4Cg.."\'>
             
 
<id>https://spreadsheets.google.com/feeds/list/tBfPhxo_vMvgY6iPSjZzD-w/od6/private/full/chk2m</id>
              <updated>2011-04-19T07:17:57.281Z</updated>
              <category scheme="http://schemas.google.com/spreadsheets/2006";
                term="http://schemas.google.com/spreadsheets/2006#list"/>
              <title>2</title><content>name: 3, jobtitle: 2, description: 2, 
id: 2</content>
              <link rel="self" type="application/atom+xml" 
href="https://spreadsheets.google.com/feeds/list/tBfPhxo_vMvgY6iPSjZzD-w/od6/private/full/chk2m"/>
              <link rel="edit" type="application/atom+xml" 
href="https://spreadsheets.google.com/feeds/list/tBfPhxo_vMvgY6iPSjZzD-w/od6/private/full/chk2m/4cgbdjajg"/>
              <gsx:name>New Name</gsx:name>
            </entry>';

$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, 
'https://spreadsheets.google.com/feeds/list/tBfPhxo_vMvgY6iPSjZzD-w/od6/private/full/chk2m/4cgbdjajg/');
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $fields);
$response = curl_exec($curl);
$status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
curl_close($curl);

echo $response;

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Thanks.