[Skyrider]

Try using the checked="checked" value instead, like so:

PHP Code:

<vb:if condition="$show['trackpm']">
                    <li>
                        <label for="cb_receipt"><input type="checkbox" name="receipt" value="1" id="cb_receipt" tabindex="1" {vb:raw checked.receipt} checked="checked"/> {vb:rawphrase request_receipt_for_message}</label><p class="description">{vb:rawphrase request_receipt_for_message_desc}</p>
                    </li>
                    </vb:if>