components/com_jssupportticket/views/ticket/tmpl/formticket.php line 526:
<input type="hidden" name="uid" id="uid" value="<?php echo $this->editticket->uid;?>" />
Should be:
<input type="hidden" name="uid" id="uid" value="<?php if (isset($this->editticket)) echo $this->editticket->uid;?>" />