Error with Orbeon Forms

Question

We have an older application based on Orbeon forms 4.4. Out of the blue, we started having a problem where various links and buttons on certain forms are not functioning correctly. The forms impacted seem to be Orbeon's built-in Forms Builder and a few of our forms that use the Orbeon "Wizard" view...the initial page displays properly, but navigation from one section to another seems to be broken.

The only unusual thing we see in the log files is this message:

WARN  XmlLibraryChecker  - Looking for a valid Parser...
Checking for Xerces, found version Xerces-J 2.11.0 needed version Xerces-J 2.9.0
Warning: Failed find a valid Parser!

Please add an appropriate Parser to the class-path, e.g. in the 'endorsed' folder of the servlet container or in the 'endorsed' folder of the JRE.

In the Orbeon webapps/orbeon/WEB-INF/lib directory, we see a xerces-2.11-orbeon.jar all of the JAR files in this directory are dated November 2013 and have not been changed best we can tell. I understand this is a "Warn" message, but there doesn't seem to be any other sign of problem.

In the case of Form Builder, we go to the listing of all the current forms, and are unable to page through the list. When we click on the paging control at the bottom of the page, we see an HTTP request to "xforms-server" from "connection.js:467". The data sent on this request is:

<!DOCTYPE xxf:event-request [<!ENTITY nbsp "&#160;">]>
<xxf:event-request xmlns:xxf="http://orbeon.org/oxf/xml/xforms">
    <xxf:uuid>a3a297feb1356b5190ce1050fdc165bfadae85e3</xxf:uuid>
    <xxf:sequence>2</xxf:sequence>
    <xxf:action>
        <xxf:event name="DOMActivate" source-control-id="xf-432"></xxf:event>
    </xxf:action>
</xxf:event-request>

This seems to work (HTTP response code 200) and we seem to get a response that has the next page worth of values in a long XML format. The display at the browser is unchanged however...the list of displayed items in Form Builder doesn't move or change in any way.

The pattern in our "Wizard View" forms is similar...we see the same HTTP transaction sent to the server, get a similar XML response, but no display update occurs.

Clients are Chrome 58 and 60, plus Safari 10.1.2.

Server side is Tomcat 7 with Java 1.7.051 and MySQL as the persistence layer.