Clicking on the Home Nuxeo Drive tab produces an error

When I click on the Nuxeo Drive tab of my Home, I get an error that says "/incl/nuxeodrive/synchronization_roots.xhtml @13,49 <a4j:form> Tag Library supports namespace: http://richfaces.org/a4j, but no tag was defined for name: form".
See complete stacktrace attached.