undefined index error when submitting form and inserting values into database?

I am using the following HTML form:

<form name="request" action="include/process_ns_request.php" onsubmit="return ValidateNewSupplierRequest()" method="POST">

<input type="text" id="comp_name" placeholder="Company Name" class="login_form2"/>

<select class="login_form2_select" id="comp_type">
  <option value="" disabled selected>Select Company Type</option>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>  


<input type="text" id="comp_reg" placeholder="Company Reg. Number" class="login_form2" />

<select class="login_form2_select" disabled id="address">
  <option value="" disabled selected>Select Address Line</option>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>


<input type="text" id="vat_numb" placeholder="Company VAT Number" class="login_form2" />

<input type="text" id="postcode" placeholder="Postcode" class="login_form2" />

<input type="text" id="cont_name" placeholder="Contact Name" class="login_form2" />

<input type="text" id="cont_email" placeholder="Contact Email" class="login_form2" />



<input type="text" id="cont_tel" placeholder="Contact Tel. Number" class="login_form2" />

<input type="text" id="conf_email" placeholder="Confirm Contact Email" class="login_form2" />



<input type="text" id="cont_mob" placeholder="Mobile Number (Optional)" class="login_form2" />

<input type="text" id="promo" placeholder="Promotional Code" class="login_form2" />


<input type="submit" value="Submit">

</form>

i am then posting my form data to my mysql query page: process_ns_request.php

 <?php 
    session_start();
    include("config.php");

    if (isset($_POST['request'])) {
    // do stuff
    //retrieve our data from POST
    $comp_name = $_POST['comp_name'];
    $comp_reg = $_POST['comp_reg'];
    $comp_type = $_POST['comp_type'];
    $address = $_POST['address'];
    $postcode = $_POST['postcode'];
    $vat_numb = $_POST['vat_numb'];
    $cont_name = $_POST['cont_name'];
    $cont_email = $_POST['cont_email'];
    $conf_email = $_POST['conf_email'];
    $cont_tel = $_POST['cont_tel'];  
    $cont_mob = $_POST['cont_mob'];



    $comp_name = stripslashes($comp_name);
    $comp_name = mysql_real_escape_string($comp_name);
    $comp_reg = stripslashes($comp_reg);
    $comp_reg = mysql_real_escape_string($comp_reg);
    $comp_type = stripslashes($comp_type);
    $comp_type = mysql_real_escape_string($comp_type);
    $address = stripslashes($address);
    $address = mysql_real_escape_string($address);
    $postcode = stripslashes($postcode);
    $postcode = mysql_real_escape_string($postcode);
    $vat_numb = stripslashes($vat_numb);
    $vat_numb = mysql_real_escape_string($vat_numb);
    $cont_name = stripslashes($cont_name);
    $cont_name = mysql_real_escape_string($cont_name);
    $cont_email = stripslashes($cont_email);
    $cont_email = mysql_real_escape_string($cont_email);
    $conf_email = stripslashes($conf_email);
    $conf_email = mysql_real_escape_string($conf_email);
    $cont_tel = stripslashes($cont_tel);
    $cont_tel = mysql_real_escape_string($cont_tel);
    $cont_mob = stripslashes($cont_mob);
    $cont_mob = mysql_real_escape_string($cont_mob);


    }else{
        echo 'form was not submitted';
    }



    $query = "INSERT INTO new_supplier_request (id, reference, user_id, date, status, payment_term) VALUES ('', '123','2', now(), 'Pending', '$comp_name')";
    echo 'ok';
    ?>

However, I get an index undefined error for all my variables. can someone please show me what i'm doing wrong? Thanks in advance