We're sorry Data from Microsoft SQL Server Reporting Services reports can only be imported from the PowerPivot window if ...

We're sorry – Data from Microsoft SQL Server Reporting Services reports can only be imported from the PowerPivot window if Microsoft .NET Framework 4.0 is installed. If you don't have it installed, you can get it from Microsoft .NET Framework 4 (Web Installer).

Alternatively, you can import Reporting Services reports into the data model from Excel using the regular Data Feed option. In Excel, go to the Data tab > From Other sources > From OData Data Feed. The data is then available to both Excel and PowerPivot.