Key Not Found exception with Managed Operation

inside of a simple action after adding all of the appropriate Xafari modules to the WinModule, NOT the client agnostic one, I get "Key not found" while instantiating the ManagedOperation within the execute event handler.

am I doing anything wrong?
private void EligibilityCheckAction_Execute(object sender, SimpleActionExecuteEventArgs e)
{
//exception is here
var mo = new ManagedOperation(Application)
{
ZoneType = ManagedOperationZoneTypes.Local,
Name = "Managed operation with progress bar",
TotalStep = e.SelectedObjects.Count
};
mo.ProcessCode = o =>
{
for (var i = 1; i <= e.SelectedObjects.Count; i++)
{

//... Do stuff here

xpos.CommitChanges();
o.NextStep($"Result Message",i, e.SelectedObjects.Count);
}
}
};
mo.Start();
SyncManagedOperationHelper.CreateHelper(mo).InitShowViewParametersProgress(e.ShowViewParameters,true);
}