the first time around that link dod not exist for me, perhaps in the future a direct link to the page would be better?
anyway,, the hidden field used to pass the ID of the record to update was missing from the page:
<input type="hidden" name="WADAUpdateRecordID" id="WADAUpdateRecordID" value="<?php echo((isset($_GET["invalid"])?ValidatedField("lodgesupdate","WADAUpdateRecordID"):$_GET["ActivityID"])); ?>" />