500 Server error on insert form

I have done dozens of insert forms with no problem. However I have a very simple insert form that does not submit and throws a 500 Server error.

Screen Shot 2018-10-30 at 12.27.13 PM.png1944×160 31.2 KB

<form id="formAddComment" method="post" is="dmx-serverconnect-form" action="dmxConnect/api/employers/profile/forms/addcomments.php" dmx-on:success="commentsshortlist.load({});commentsfulllist.load({})">
                    <div class="form-group">
                      <input type="hidden" class="form-control" id="hiddenempidcomments" name="hiddenempidcomments" aria-describedby="input4_help" placeholder="Enter some text" dmx-bind:value="query.profile">
                    </div>
                    <div class="form-group">
                      <input type="hidden" class="form-control" id="hiddencommentsstafffirts" name="hiddencommentsstafffirts" aria-describedby="input3_help" placeholder="Enter some text" dmx-bind:value="userdetails.data.query1[0].staffFirst">
                    </div>
                    <div class="form-group">
                      <input type="hidden" class="form-control" id="hiddencommentsstafflast" name="hiddencommentsstafflast" aria-describedby="input2_help" placeholder="Enter some text" dmx-bind:value="userdetails.data.query1[0].staffLast">
                    </div>
                    <div class="form-group">
                      <input type="hidden" class="form-control" id="hiddencommentsdate" name="hiddencommentsdate" aria-describedby="input1_help" placeholder="Enter some text" dmx-bind:value="var1.datetime.formatDate(&quot;yyyy-MM-dd&quot;)">
                    </div>
                    <div class="form-group">
                      <textarea id="textareaEmployerComment" class="form-control" required=""></textarea>
                    </div>
                    <button class="btn btn-warning btn-sm btn-block" type="submit">Add Comment</button>
                  </form>