404 Error When Form Is Submitted

Hi,

I’m attempting to validate a birthday. When I let the user choose there birthday and press “submit” I’m getting a 404 error message. I don’t know why this is the case. I was hoping someone can look at my below syntax and tell me what you think I’m doing wrong.

Thanks

Syntax

HTML

<form action="" id="contactFormUs" name="contactFormUs" method="post" class="forms-contact formsec">

	  <div class="pro_fields">
          <li>
            <label for="first_Name">
              <?php _e('First Name:','language');?>
            </label>
            <br/>
            <?php $first_Name = $_POST['first_Name'];
				if($first_Name != '' && $first_Name != 'Please Enter Your First Name'){
				$first_Name = $_POST['first_Name'];
				$first_Name_Submitted = trim_and_cap_it_out($_POST['first_Name']);
			}
            ?>
            <input type="text" name="first_Name" id="first_Name" class="field" value="<?php echo $first_Name_Submitted; ?>"/>
            <?php if($first_name_error != '') { ?>
            <span class="error">
            <?=$first_name_error;?>
            </span>
            <?php } ?>
          </li>
        </div>

		<div class="pro_fields">
          <li>
            <label for="birthday">
              <?php _e('Birthday:','language');?>
            </label>
            <br/>

			<select name="month" id="month" style="width:200px">
			<option value="0">--Select A Month--</option>
				<option <?php if ($_REQUEST['month'] == 1) { ?>selected="true" <?php }; ?>value="January">January</option>
				<option <?php if ($_REQUEST['month'] == 2) { ?>selected="true" <?php }; ?>value="February">February</option>
				<option <?php if ($_REQUEST['month'] == 3) { ?>selected="true" <?php }; ?>value="March">March</option>
				<option <?php if ($_REQUEST['month'] == 4) { ?>selected="true" <?php }; ?>value="April">April</option>
				<option <?php if ($_REQUEST['month'] == 5) { ?>selected="true" <?php }; ?>value="May">May</option>
				<option <?php if ($_REQUEST['month'] == 6) { ?>selected="true" <?php }; ?>value="June">June</option>
				<option <?php if ($_REQUEST['month'] == 7) { ?>selected="true" <?php }; ?>value="July">July</option>
				<option <?php if ($_REQUEST['month'] == 8) { ?>selected="true" <?php }; ?>value="August">August</option>
				<option <?php if ($_REQUEST['month'] == 9) { ?>selected="true" <?php }; ?>value="September">September</option>
				<option <?php if ($_REQUEST['month'] == 10) { ?>selected="true" <?php }; ?>value="October">October</option>
				<option <?php if ($_REQUEST['month'] == 11) { ?>selected="true" <?php }; ?>value="November">November</option>
				<option <?php if ($_REQUEST['month'] == 12) { ?>selected="true" <?php }; ?>value="December">December</option>
			</select>

			<select name="day" id="day" style="width:200px">
				<option value="0">--Select A Day--</option>
				<option <?php if ($_REQUEST['day'] == 1) { ?>selected="true" <?php }; ?>value="1">1</option>
				<option <?php if ($_REQUEST['day'] == 2) { ?>selected="true" <?php }; ?>value="2">2</option>
				<option <?php if ($_REQUEST['month'] == 3) { ?>selected="true" <?php }; ?>value="3">3</option>
				<option <?php if ($_REQUEST['month'] == 4) { ?>selected="true" <?php }; ?>value="4">4</option>
				<option <?php if ($_REQUEST['month'] == 5) { ?>selected="true" <?php }; ?>value="5">5</option>
				<option <?php if ($_REQUEST['month'] == 6) { ?>selected="true" <?php }; ?>value="6">6</option>
				<option <?php if ($_REQUEST['month'] == 7) { ?>selected="true" <?php }; ?>value="7">7</option>
				<option <?php if ($_REQUEST['month'] == 8) { ?>selected="true" <?php }; ?>value="8">8</option>
				<option <?php if ($_REQUEST['month'] == 9) { ?>selected="true" <?php }; ?>value="9">9</option>
				<option <?php if ($_REQUEST['month'] == 10) { ?>selected="true" <?php }; ?>value="10">10</option>
				<option <?php if ($_REQUEST['month'] == 11) { ?>selected="true" <?php }; ?>value="11">11</option>
				<option <?php if ($_REQUEST['month'] == 12) { ?>selected="true" <?php }; ?>value="12">12</option>
				<option <?php if ($_REQUEST['month'] == 13) { ?>selected="true" <?php }; ?>value="13">13</option>
				<option <?php if ($_REQUEST['month'] == 14) { ?>selected="true" <?php }; ?>value="14">14</option>
				<option <?php if ($_REQUEST['month'] == 15) { ?>selected="true" <?php }; ?>value="15">15</option>
				<option <?php if ($_REQUEST['month'] == 16) { ?>selected="true" <?php }; ?>value="16">16</option>
				<option <?php if ($_REQUEST['month'] == 17) { ?>selected="true" <?php }; ?>value="17">17</option>
				<option <?php if ($_REQUEST['month'] == 18) { ?>selected="true" <?php }; ?>value="18">18</option>
				<option <?php if ($_REQUEST['month'] == 19) { ?>selected="true" <?php }; ?>value="19">19</option>
				<option <?php if ($_REQUEST['month'] == 20) { ?>selected="true" <?php }; ?>value="20">20</option>
				<option <?php if ($_REQUEST['month'] == 21) { ?>selected="true" <?php }; ?>value="21">21</option>
				<option <?php if ($_REQUEST['month'] == 22) { ?>selected="true" <?php }; ?>value="22">22</option>
				<option <?php if ($_REQUEST['month'] == 23) { ?>selected="true" <?php }; ?>value="23">23</option>
				<option <?php if ($_REQUEST['month'] == 24) { ?>selected="true" <?php }; ?>value="24">24</option>
				<option <?php if ($_REQUEST['month'] == 25) { ?>selected="true" <?php }; ?>value="25">25</option>
				<option <?php if ($_REQUEST['month'] == 26) { ?>selected="true" <?php }; ?>value="26">26</option>
				<option <?php if ($_REQUEST['month'] == 27) { ?>selected="true" <?php }; ?>value="27">27</option>
				<option <?php if ($_REQUEST['month'] == 28) { ?>selected="true" <?php }; ?>value="28">28</option>
				<option <?php if ($_REQUEST['month'] == 29) { ?>selected="true" <?php }; ?>value="29">29</option>
				<option <?php if ($_REQUEST['month'] == 30) { ?>selected="true" <?php }; ?>value="30">30</option>
				<option <?php if ($_REQUEST['month'] == 31) { ?>selected="true" <?php }; ?>value="31">31</option>
			</select>

			<!--<select name="year" id="year" style="width:200px">
				<option value="0">--Select A Year--</option>
				<?php for($i=date("1900"); $i<=date("1997")+2; $i++)
						if($year == $i)
							echo '<option value='.$i.' selected="true">'.$i.'</option>';
						else
							echo '<option value='.$i.'>'.$i.'</option>';
				?>
			</select>-->

            <?php if($birthdayNumberError != '0') { ?>
            <span class="error">
            <?=$birthdayNumberError;?>
            </span>
            <?php } ?>
          </li>
        </div>

       <div class="pro_fields">
          <div style="clear:both"></div>
          <input type="submit" name="submitted" id="submitted" class="send-contact" value="Send"/>
          <div style="clear:both"></div>
        </div>

        	<hr>
        </div>

      </form>

PHP Syntax

if(isset($_POST['submitted'])) {	

	function validate_information($string){
		if(trim($string) === '' && empty($string)){
			return true;
		} else {
			return false;
		}
	}

	function validate_singleDropDownMenus($string){
		if(isset($string) && $string === '0' ){
			return true;
		} else {
			return false;
		}
	}

	function trim_and_cap_it_out($string){
		$trimmed = trim($string);
		$lowerCase = strtolower($trimmed);
		$uppercaseValue = ucfirst($lowerCase);
		return $uppercaseValue;
	}

	$first_Name = $_POST['first_Name'];
    if(validate_information($first_Name)){
	  $first_name_error = __('<span STYLE="font-size: x-medium; color: #000000">Enter Your First Name</span>','language');
      $error_message .= 'Enter Your First Name\n';
      $hasError = true;
    } else {
      $first_Name = trim($first_Name);
	  $first_Name = strtolower($first_Name);
	  $first_Name = ucfirst($first_Name);
    }

	$month			= $_REQUEST['month'];
	$day 			= $_REQUEST['day'];
	$year		  	= $_REQUEST['year'];

	// var_dump($month);
	// var_dump($day);
	// die(); 

	if(checkdate($month,$day,$year)){
		//$dob is a valid date
		echo "<p>Date of birth:$day $month $year</p>";
	} else {
		//$dob is a not valid date
		$day = null;
		$month = null;
		$year = null;
		echo "<p><b><font color=red>Please enter a <mark>valid</mark> date of birth!</font></b></p>";
	}
}