When working with Excel services in SharePoint, you often need to publish part of the workbook which will be made visible to normal users.
But it gets a little tricky when you have Pivot Charts under your defined named range items. If the Pivot Chart and related Pivot Table are not in the same worksheet - named range will not appear as one of the options to enable for publishing. You need to make sure that both Pivot Chart and Pivot Table are on the same sheet.