If you happen to install PowerPivot on a SharePoint server that has prior SQL Server installation (SQL engine, Analysis Services, Reporting Services etc.) you will run into problems.
You may see error that the installation was unable to register Microsoft.AnalysisServices.SharePoint.Integration.dll assembly. Or if you are really lucky, you may get by far more helpful error message “Object reference not set to an instance of an object”.
You generally need 3 steps in order to bypass these errors:
1.prepare setup100.exe.config file:
Save following code in a file named setup100.exe.config and copy the file into %ProgramFiles%Microsoft SQL Server100Setup BootstrapSQLServer2008R2x64 directory.
<?xml version=”1.0″ encoding=”utf-8″ ?>
<disableCachingBindingFailures enabled=”1″ />
Check this TechNet article for more details.
2.manually copy Microsoft.AnalysisServices.SharePoint.Integration.dll to the C:Program FilesMicrosoft SQL Server100SDKAssemblies directory. If you already had one unsuccessful run at installing PowerPivot, you will find this file in C:Program Files (x86)Microsoft SQL Server100SDKAssemblies. If you could find the dll somewhere on the internet AND trust the source, by all means download it. I prefer not to place publicly downloaded dlls on my production servers.
3.modify the ConfigurationFile.ini file
When running the PowerPivot installation wizard, the SharePoint Central Administration port is not being configured correctly by default. The installation fails with “unable to communicate” error message. It is therefore necessary that we manually modify the contents of the setup file before proceeding with the installation.
Before clicking Finish at the PowerPivot installation screen, open and modify the ConfigurationFile.ini which can be found in the C:Program FilesMicrosoft SQL Server100Setup BootstrapLog<date-Time> (automatically created each time you run PowerPivot installation wizard). Look for FARMADMIN port entry and modify the port number to your central administration port.