I made some changes, but still very confused about a few things since this is my first time validating a form using php. So, I am not very sure if I am doing things right this time around. 
My error console also tells me that there is an error on line 43 char 1 (Object expected).
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Contact</title>
<link href="style.css" rel="stylesheet" type="text/css" />
<script type="text/javascript">
function ValidateContactForm()
{
if (document.getElementById("message").value === "")
{
window.alert("Please provide a detailed description or comment.");
document.getElementById("message").focus();
}
if (document.getElementById("author").value === "")
{
window.alert("Please provide your name.");
document.getElementById("author").focus();
}
if (document.getElementById("verif_box").value === "")
{
window.alert("Please enter captcha code.");
document.getElementById("verif_box").focus();
}
function checkEmail()
{
var email = document.getElementById("email");
var filter = /^([a-zA-Z0-9_\\.\\-])+\\@(([a-zA-Z0-9\\-])+\\.)+([a-zA-Z0-9]{2,4})+$/;
if (!filter.test(email.value))
{
alert('Please provide a valid email address');
email.focus;
}
return true; // successful
}
return false; // failed validation
}
</script>
</head>
<body onload="startform()">
<div id="templatemo_wrapper">
<div id="templatemo_header">
<ul id="social_box">
<li><a href="http://www.facebook.com/"><img
src="http://www.sitepoint.com/forums/images/facebook.png" alt="facebook" /></a></li>
<li><a href="http://www.twitter.com/"><img src="http://www.sitepoint.com/forums/images/twitter.png"
alt="twitter" /></a></li>
</ul>
<div id="site_title">
<h1><a href="index.htm"><img src="http://www.sitepoint.com/forums/images/logo2.png" alt="logo"
/><span></span></a></h1>
</div> <!-- end of site_title -->
<!-- end of templatemo_menu -->
<div id="templatemo_content_wrapper">
<div id="templatemo_content_top"></div>
<div id="templatemo_content">
<h2>Contact</h2>
<p><b>E-mail: myemailaddress@gmail.com </b></p>
<p><b><a href="http://www.twitter.com/">Twitter</a></b></p>
<div class="cleaner_h50"></div>
<div id="contact_form">
<h4>Quick Contact</h4>
<form method="post" name="contact" id="contact" action="email.php"
onsubmit="return ValidateContactForm() && checkEmail();" onset="location.reload()">
<div class="col_w340 float_l">
<label for="author">Name (* Required):</label> <input
name="author" type="text" class="input_field" id="author" maxlength="40" />
<div class="cleaner_h10"></div>
<label for="subject">Subject:</label> <input name="subject" type="text" class="input_field"
id="subject" maxlength="40" />
<div class="cleaner_h10"></div>
<label for="email">Email (* Required):</label> <input
name="email" type="text" class="input_field" id="email" maxlength="40" />
<div class="cleaner_h10"></div>
Type verification image:<br />
<input name="verif_box" type="text" id="verif_box" style="padding:2px; border:1px solid
#CCCCCC; width:180px; height:14px;font-family:Verdana, Arial, Helvetica, sans-serif;
font-size:11px;"/>
<img src="verificationimage.php?<?php echo rand(0,9999);?>" alt="verification image, type it
in the box" width="50" height="24" align="absbottom" /><br />
<br />
</div>
<div class="col_w340 float_r">
<label for="message">Message (*Required):</label> <textarea
id="message" name="message" rows="0" cols="0" class="required"></textarea>
<div class="cleaner_h10"></div>
<input type="submit" class="submit_btn float_l" name="submit"
id="submit" value="Send" />
<input type="reset" class="submit_btn float_r" name="reset"
id="reset" value="Reset" />
</div>
</form>
</div>
<div class="cleaner"></div>
</div>
<div id="templatemo_content_bottom"></div>
</div>
<div id="templatemo_sp_box">
<div class="col_w340 float_l">
</div>
</div>
<div class="col_w340 float_r">
</div>
</div>
</div>
<div id="templatemo_footer">
Copyright © 2011 <a href="www.twitter.com/">Starr</a><br/>
<a href="http://www.iwebsitetemplate.com" target="_parent">Website Templates</a>
by <a href="http://www.templatemo.com" target="_parent">Free CSS Templates</a>
</div> <!-- end of templatemo_footer -->
</div> <!-- end of templatemo_wrapper -->
</body>
</html>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Contact</title>
<link href="style.css" rel="stylesheet" type="text/css" />
</head>
<body>
<?php
//First you need to make sure the form is sent and everything is there.
if($_SERVER['REQUEST_METHOD'] == 'POST'){
//Was everything sent? (it should have been, even empty fields)
if(!isset($_POST['name'], $_POST['email'], $_POST['subject'], $_POST['message'])){
echo '<b>Form error</b> - Not everything was sent in the form.';
}else{
//Set the variables to the form values
$first_name=$_POST['name'];
$email_address=$_POST['email'];
$subject=$_POST['subject'];
$message=$_POST['message'];
/*
* If their lengths are zero, output an error.
*
* There are better, cleaner ways of going through
* each one, but I'm guessing PHP isn't a strength
* and therefore it's better to be simple with the code.
*
*/
if(strlen($first_name) == 0){
echo '<p><b>Empty Field</b> - Please provide your first Name</p>';
}else if(strlen($email_address) == 0){
echo '<p><b>Empty Field</b> - Please provide your email Address</p>';
}else if(strlen($subject) == 0){
echo '<p><b>Empty Field</b> -Please provide a subject</p>';
}else if(strlen($message) == 0){
echo '<p><b>Empty Field</b> -Please provide your message</p>';
}else{
$Sent = mail("myemailaddress@gmail.com","Subject: {$subject}", $message, "From:
$first_name <{$email_address}>");
if($Sent){
echo 'Success! :D';
}else{
echo 'Please make sure that all fields are filled out';
}
}
}
}
?>
</body>
</html>