Fix Invalid postback or callback argument error in curl scraping data post

Question

I am scraping this website using curl. It has a form(left one) that need to submit using curl.

What I have done: If you see my code, first curl_exec is working fine and I am getting captcha code and other attributes perfectly. In 2nd curl_exec, when I am posting all attributes in form, then I got error.

My code is here:

$url = 'http://epunjabschool.gov.in/gs_schoolwebsite/Search.aspx';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_PROXY, $proxy); 
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 50);
curl_setopt($ch, CURLOPT_TIMEOUT, 50);

$httpCode = curl_getinfo($ch , CURLINFO_HTTP_CODE); // this results 0 every time
$response = curl_exec($ch);

if ($response === false){ 
    $response = curl_error($ch);
echo stripslashes($response);
}

//curl_close($ch);

$dom = new DOMDocument;

@$dom->loadHTML($response);
$tags = $dom->getElementsByTagName('input');
$VIEWSTATE = '';
$EVENTVALIDATION = '';
for($i=0;$i<$tags->length; $i++){
    $grab = $tags->item($i);
    //echo $grab->getAttribute('value');
    if($grab->getAttribute('name') === '__VIEWSTATE'){
    $VIEWSTATE = $grab->getAttribute('value');
    }
    if($grab->getAttribute('name') === '__EVENTVALIDATION'){
    $EVENTVALIDATION = $grab->getAttribute('value');
    }
}



$domx = new DOMXPath($dom);
$trans_id = $domx->query('//img[@id="imgCaptcha"]');
$imgCaptcha = '';
foreach ($trans_id as $id) {
    $imgCaptcha =  $id->getAttribute('src');
}
$captch = explode('=', $imgCaptcha);
echo $captcha = $captch[1];


$data = array(
    "__VIEWSTATE" => $VIEWSTATE,
    "__EVENTVALIDATION" => $EVENTVALIDATION,
    "__EVENTARGUMENT" => '',
    "__EVENTTARGET" => '',
    "__LASTFOCUS" => '',
    "txtCaptcha" => $captcha,
    "ddlDistrict" => 2,
    "ddlEdBlock" => 2,
    "ddlManagement" => 1,
    "ddlCategory" => 4,
    "ddlDistrictBySchoolName" => "Select",
    "btnShow" => "Show",
    "txtCaptchbySchoolName" => "",
    "txtSchoolName" => ""
);

$url = 'http://epunjabschool.gov.in/gs_schoolwebsite/Search.aspx';
$headers = array("Content-Type: application/x-www-form-urlencoded");
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, TRUE);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_POST, TRUE);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data));
curl_setopt($ch, CURLOPT_COOKIEJAR, "cookie.txt");
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);

if ($response === false){ 
    $response = curl_error($ch);
}
echo stripslashes($response);

Issue: This is error I am getting:

Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them.