Here is the entire code for the small app:

            DataTable table = new DataTable();
            table.Columns.Add("Name", typeof(String));
            table.Columns.Add("Value", typeof(double));

            ultraCalcManager.NamedReferences.Add("NAV", "0");

            DataRow row = table.NewRow();
            row["Name"] = "John";
            row["Value"] = 5;

            table.Rows.Add(row);

            ultraGrid1.DataSource = table;

and in initialize layout:

            UltraGridColumn column = ultraGrid1.DisplayLayout.Bands[0].Columns.Add("Formula");
            column.DataType = typeof(double);
            column.Formula = "[Value] / [//NAV]";
            column.FormulaErrorValue = 0;

 I hooked up all of the Error events of the UltraCalcManager but I'm just expecting FormulaCalculationError to fire but it does not.

 Which events are you referring to and when are they not fired?

 OK, so I realize now that FormulaErrorValue doesn't specify the text to display in the cell, merely the formula to pass along to the data source.  But why are none of the UltraCalcManager events being fired?

 I created a small demo project and wasn't able to reproduce it like I had expected.  I create a data table with 2 columns, name(string) and value(double).  I add a row to the table and bind the grid to this.  I add a named reference with a formula of "0" and create a column of data type double with formula = "[value] / [//reference]" and infinity is displayed as cell text.  I set the formula error value to 0 but still see infinity.  Also, no error events of the UltraCalcManager are fired.  Shouldn't the cell text become 0 and shouldn't some events be firing to let me know that I am attempting to divide by zero?