What is wrong in this

<?php
$EmailFrom = " Sites Subscription";
$EmailTo = "[email protected]";
$Subject = "New User Submission";
$E_mail = Trim(stripslashes($_POST['email'])); 

$validationOK=true;
if (!$validationOK) {
  print "<meta http_equiv=\"refresh\" content=\"0;URL=error.htm\">";
  exit;
}

$Body = "";
$Body .= "E_mail: ";
$Body .= $E_mail;
$Body .= "\n";

// send email 
if (isset($_POST['email'])) {
$success = mail($EmailTo, $Subject, $Body, "From: <$EmailFrom>");
}
// redirect to success page 
if ($success){
echo "thank you for submission. You will receive new proxies almost every day. To unsubscribe please send me a mail directly at the email listed at the top of the main site";
} else { 
echo "Error... Try again... <form action=\"" . $_SERVER["SCRIPT_NAME"] ."\" method=\"POST\"><br /><br />Email: <input type=\"text\" name=\"email\" /><input type=\"submit\" value=\"Submit\"";
}

?>