cURL not sending form entries

[existatus]

In a form there are entries like this:

<input type="text" name="first_name" size="24" />
<input type="text" name="last_name" size="24" />

<input type="hidden" name="must_have" value="12345" />

<input type="hidden" name="recipient" value="myemail@comcast.net" />
<input type="hidden" name="redirect" value="http://mywebsite.com" />
<input type="hidden" name="subject" value="Topic In Question" />

When the action in the form is set to go directly to the receiving file like this:

<form method="post" action="http://theirwebsite/receive.jsp" [name="goodname">

everything works. The entries are received by http://theirwebsite/receive.jsp.

However, I need to use a separate file to send the form entries, so the action is set like this:

<form method="post" action="http://mywebsite/separate.php" name="goodname">

Code in http://mywebsite/separate.php is like this:

<?php 
$siteUrl="http://theirwebsite/receive.jsp/";
 $variablesToPost = array 
( 
"first_name", 
"last_name", 
"must_have", 
"recipient", 
"redirect", 
"subject" 
); 

$postData= array(); foreach($variablesToPost as $variable) 
{ 
$postData[] = $variable . '=' . htmlspecialchars($_REQUEST[$variable]); 
} 
$postData = encodeQueryString(implode('&', $postData));
 
$curl = curl_init(); 
curl_setopt($curl, CURLOPT_URL, $siteUrl); 
curl_setopt($curl, CURLOPT_POST, 1); 
curl_setopt($curl, CURLOPT_POSTFIELDS, $postData); 
curl_exec ($curl); curl_close ($curl); 
?>

The entries can be printed from the separate file, so I know they get there.

All spelling has been checked carefully. All hidden fields required by the destination file are listed in the array.

The values are now not received by http://theirwebsite/receive.jsp, so something must be wrong with the code.