Check that vClassGroup is non-null to prevent errors on the page

webapp/web/templates/freemarker/body/partials/menupage/menupage-checkForData.ftl

@@ -2,12 +2,15 @@
 
 <#assign populatedClasses = 0 />
 
+<#if vClassGroup??> <#-- the controller may put a null -->
     <#list vClassGroup as vClass>
         <#-- Check to see if any of the classes in this class group have individuals -->
         <#if (vClass.entityCount > 0)>
             <#assign populatedClasses = populatedClasses + 1 />
         </#if>
     </#list>
+</#if>
+
 <#if (populatedClasses == 0)>
     <#assign noData = true />
 <#else>