Checkbox added validation error

Good evening,
Your plugin is really awesome but I had found a problem I can’t solve by myself.
I read in another forum the way to add a checkbox to comment area, (it’s necessary to accept our terms and conditions).
The problem I have, is that it can’t get through validation, cause I get the error:

TypeError: e[w] is not a functionk @ validator.min.js?ver=1.0.0:2o @ validator.min.js?ver=1.0.0:2(anonymous function) @ validator.min.js?ver=1.0.0:2n.extend.each @ jquery.js?ver=1.12.3:2n.fn.n.each @ jquery.js?ver=1.12.3:2n @ validator.min.js?ver=1.0.0:2(anonymous function) @ wpdiscuz.min.js?ver=3.2.8:2n.event.dispatch @ jquery.js?ver=1.12.3:3r.handle @ jquery.js?ver=1.12.3:3

What I have done so far is just edit file class.WpdiscuzHelper.php
and add the line:

<div class="wc_terms_checkbox" style="display:block">

                                    <input type="checkbox" id="wpdiscuz_terms" value="terms" name="wpdiscuz_terms" class="wc_terms-<?php echo $uniqueId; ?>">
                                    <label class="wc-label-comment-notify" for="wc_notification_new_comment-0_0"><?php echo __('I accept the <a href="privacidad" target="_blank">terms and Conditions</a>', 'wpdiscuz'); ?></label>
                                </div>

just before
<input type="button" class="wc_comm_submit button alt" value="<?php echo $this->optionsSerialized->phrases['wc_submit_text']; ?>" name="submit">

Could you please help me?

https://wordpress.org/plugins/wpdiscuz/