PHP email script, I receive emails but "from:Mail failure - malformed recipient addre

I have a script on my website and its working somewhat? I receive form data but.. the from say "Mail failure - malformed recipient address" on hostgator. I get the subject and message but not the email address from the form. How could I fix this?

<form action="send_mail.php" method="post">
             <input name="name" type="text" placeholder="Your Name...">
             <input name="email_address" type="email" placeholder="Your Email...">
             <textarea name="message" placeholder="Your Message..."></textarea>
             <input type="submit" value="Submit &rarr;" class="dropsubmitbtn">
</form>

Code (markup):

<?php
/*
This first bit sets the email address that you want the form to be submitted to.
You will need to change this value to a valid email address that you can access.
*/
$webmaster_email = "support@****.com"; /* ENTER EMAIL ADDRESS TO THE LEFT INSIDE THE QUOTES */

/*
This bit sets the URLs of the supporting pages.
If you change the names of any of the pages, you will need to change the values here.
*/
$feedback_page = "index.html";
$error_page = "error.html";
$thankyou_page = "thanks.html";

/*
This next bit loads the form field data into variables.
If you add a form field, you will need to add it here.
*/
$name = $_REQUEST['name'] ;
$email_address = $_REQUEST['email_address'] ;
$comments = $_REQUEST['message'] ;

/*
The following function checks for email injection.
Specifically, it checks for carriage returns - typically used by spammers to inject a CC list.
*/
function isInjected($str) {
	$injections = array('(\n+)',
	'(\r+)',
	'(\t+)',
	'(%0A+)',
	'(%0D+)',
	'(%08+)',
	'(%09+)'
	);
	$inject = join('|', $injections);
	$inject = "/$inject/i";
	if(preg_match($inject,$str)) {
		return true;
	}
	else {
		return false;
	}
}

// If the user tries to access this script directly, redirect them to the feedback form,
if (!isset($_REQUEST['email_address'])) {
header( "Location: $feedback_page" );
}

// If the form fields are empty, redirect to the error page.
elseif (empty($email_address) || empty($comments)) {
header( "Location: $error_page" );
}

// If email injection is detected, redirect to the error page.
elseif ( isInjected($email_address) ) {
header( "Location: $error_page" );
}

// If we passed all previous tests, send the email then redirect to the thank you page.
else {
mail( "$webmaster_email", "Message from your Free Lol RP site",  
  $name, $comments, "From: $email_address" );
header( "Location: $thankyou_page" );
}
?>

Code (markup):

 

There is no such thing as

[/FONT][FONT=courier new]<input type="email" placeholder="Your email..." />[/FONT][FONT=courier new]

Code (markup):

What you should have used instead is:

<input type="text" value="Your email" />

Code (markup):

There are no such properties as "email" and "placeholder" in the W3C HTML standards. I suspect this is the reason for your code failing. Remember that <input type="text" /> is the correct format here.

 

I changed it to

<form action="send_mail.php" method="post">
             <input name="name" type="text" placeholder="Your Name...">
             <input name="email_address" input type="text" value="Your email" />
             <textarea name="message" placeholder="Your Message..."></textarea>
             <input type="submit" value="Submit &rarr;" class="dropsubmitbtn">
</form>

Code (markup):

and still get the same email with no "from" address