Here is a simple example that works in Jython:
errorgroup = "system"; errorkey = "allnullrequired"; params = ["PHONE"];
You can test this on the WORKORDER object and you should get this dialog:
errorgroup = "system"; errorkey = "allnullrequired"; params = java.lang.reflect.Array.newInstance(java.lang.String, 1); params = "PHONE";
Lesson learned, Jython probably works best for Automation Scripts… guess I need to start learning!