4.2.3 update broke customer login on website

The auto-update this morning caused our subscription customer login page to break.

http://www.constructionreports.com/customer-login/

The only code on that page is script for caspio:

<div id=”login” style=”padding: 20px 0 0 75px;”>
<div id=”loginTop”><script src=”https://b3.caspio.com/scripts/e1.js”></script><script&gt:// <![CDATA[
try{f_cbload(“60fb1000da389b06210b49779109″,”https:”);}catch(v_e){;} // ]]>
// ]]></script></div>
</div>

I don’t think it’s a plugin conflict, we’ve tested them all. I’m a little afraid to attempt a rollback – something I’ve never done.

What to do? Any suggestions appreciated.