The first parameter of the AddGroup method cannot be 0.

>I am trying to recreate, using the RDC, a sample .rpt file that comes with Crystal 8.5.
>I am using the following code to create a formula field in Crystal and then add a group
>
>* get the first character of the Customer.Customer Name field
>WITH oReport.FormulaFields
> oFormula = .Add("First Letter", "{Customer.Customer Name}[1]")
>ENDWITH
>* add a group
>oreport.AddGroup (0, oFormula, 14, 0)
>
>When trying to add the group I get an error "OLE error code 0x80070057: The parameter is incorrect."
>
>*the code to add a group using a database field works fine
>oField = oReport.database.tables.item(1).fields.item(1)
>oreport.AddGroup (0, oField, 14, 0)
>
>Any ideas?