If this thing were on github, I would put in for a PR...
on line 738 of mxformbuilder.class.php, can you either change the line to be
$this->modx->regClientScript($this->config['assetsUrl']."js/web/jquery.validate.min.js");
or give a setting option to allow for the validate link to be put at the bottom? Issue is that in my jQuery doesn't load until the end of the doc, and currently mxFormBuilder loads the validate script in the head (and thus it can't find jquery)
Thanks
Jason