MOSS 2007 getting exception adding a custom field to a view

Question

The following code is throwing an ArgumentException (Value does not fall within expected range):

        var formsList = Web.Current.Lists[MemForms_Constants.MementoForm_LIST_NAME];
        var allItemsView = formsList.Views["All Items"];
        var allItemsViewFields = allItemsView.ViewFields;
        var newMasterField = formTypesList.Fields.GetFieldByInternalName(newMasterInt);

        if (null != newMasterField && !allItemsViewFields.Exists(newMasterField.InternalName))
            allItemsViewFields.Add(newMasterField);

At this point, I have confirmed that newMasterField is not null. Otherwise, I cannot deduce why it would throw this exception for a new field. I wouldn't expect it to fall in the range of valid values, since it is not there yet. Please let me know if you have any suggestions.

Thanks in advance.