DW cs4 php form redirects to index, not thank you

Hi, I want my form to go to the thank you page and it goes to the homepage. Thanks for your help in advance!

Libby

      <td bgcolor="#FFFFFF"><form id="form1" name="form1" method="post" action="/gdform.php">

        <span id="sprytextfield1">

        <label for="Name">Name</label>

        <input name="Name" type="text" id="Name" size="60" />

        <span class="textfieldRequiredMsg">A value is required.</span><span class="textfieldMinCharsMsg">Minimum number of characters not met.</span><span class="textfieldMaxCharsMsg">Exceeded maximum number of characters.</span></span>

        <p><span id="sprytextfield2">

        <label for="Address">Address</label>

        <input name="Address" type="text" id="Address" size="58" />

        <span class="textfieldRequiredMsg">A value is required.</span><span class="textfieldMinCharsMsg">Minimum number of characters not met.</span><span class="textfieldMaxCharsMsg">Exceeded maximum number of characters.</span></span></p>

        <p><span id="sprytextfield3">

        <label for="City">City</label>

        <input name="City" type="text" id="City" size="35" />

        <span class="textfieldRequiredMsg">A value is required.</span><span class="textfieldMinCharsMsg">Minimum number of characters not met.</span><span class="textfieldMaxCharsMsg">Exceeded maximum number of characters.</span></span></p>

        <p><span id="sprytextfield4">

        <label for="State">State</label>

        <input name="State" type="text" id="State" size="6" />

        <span class="textfieldRequiredMsg">A value is required.</span><span class="textfieldMinCharsMsg">Minimum number of characters not met.</span><span class="textfieldMaxCharsMsg">Exceeded maximum number of characters.</span></span></p>

        <p><span id="sprytextfield5">

        <label for="Zip">Zip</label>

        <input name="Zip" type="text" id="Zip" size="10" />

        <span class="textfieldRequiredMsg">A value is required.</span><span class="textfieldMinCharsMsg">Minimum number of characters not met.</span><span class="textfieldMaxCharsMsg">Exceeded maximum number of characters.</span></span></p>

        <p><span id="sprytextfield6">

        <label for="Name on PayPal Account">Name on PayPal Account</label>

        <input type="text" name="Name on PayPal Account" id="Name on PayPal Account" />

        <span class="textfieldRequiredMsg">A value is required.</span><span class="textfieldMinCharsMsg">Minimum number of characters not met.</span><span class="textfieldMaxCharsMsg">Exceeded maximum number of characters.</span></span></p>

        <p>

          <label for="Message">Message</label>

          <textarea name="Message" id="Message" cols="55" rows="5"></textarea>

        </p>

        <p>

          <label for="Submit"></label>

          <input type="submit" name="button" id="button" value="Submit" />

        </p>

        <input type="hidden" name="receipient" id="receipient" />

        <input name="hiddenField" type="hidden" id="hiddenField" value="thankyou.html" />

      </form>