Getting error using agenda-groups. What am i doing wrong?

[cbrady321]

I am not sure what I am doing wrong.  Something I am doing is causing an error with agenda groups. 
Application throws:

/node_modules/nools/lib/agenda.js:107
            while (this.getFocusedAgenda().isEmpty() && this.getFocused() !==
                                           ^
TypeError: Cannot call method 'isEmpty' of undefined

Skipping over the gory details; I am setting up the session like:

  var session = flow.getSession();
  // register event tracing handlers
  (calls to session.on(...));

  // setup AGENDA GROUPS
  if(typeof job.groups !== "undefined"){
    var arr = job.application.rules.groups.reverse();
    for(var key in arr) {
      session.focus(arr[key]);
    }
  }

  // load and assert FACTS as type Generic
  var nt = session.flow.getDefined('Generic');
  (CODE TO RETYPE FACTs TO GENERIC)
  (calls to session.assert(fact))

  // Invoke rules engine and store results
  session.match().then(function () { ... });