I found an issue upgrading an Excel workbook containing PowerPivot data from Excel 2010 to Excel 2013. All CUBEMEMBER and CUBEVALUE functions point to a cube name that has been changed between the two version – you have to no longer reference the PowerPivot Data name, replacing it with ThisWorkbookDataModel instead.

I wrote an article describing the change that you have to manually make to these Excel formulas in this article on SQLBI web site.