MII v12.1 SP10 Patch4 - I know it is out of support

I had an older MII version handed over to me with minimal training. I am getting the following error intermittently and the only way to fix is to restart the services. 'Link execution failed: java.lang.NullPointerException: while trying to invoke the method org.w3c.dom.NodeList.getLength() of an object loaded from local variable 'nodes'. Any help appreciated