If your instance of Reporting Services is not installed in SharePoint integrated mode and you see the following error reported in your SSRS log files, don’t panic. It is expected:
library!ReportServer_0-14!be8!06/22/2012-08:36:58:: e ERROR: Throwing Microsoft.ReportingServices.Diagnostics.Utilities.OperationNotSupportedNativeModeException: , Microsoft.ReportingServices.Diagnostics.Utilities.OperationNotSupportedNativeModeException: This operation is not supported on a report server that runs in native mode.;
You can perfectly correlate it to the fact that SSRS is not configured to run in SharePoint integrated mode and the “Report Server DocumentLibrary” delivery extension is enabled.
<Extension Name="Report Server DocumentLibrary" Type="Microsoft.ReportingServices.SharePoint.SharePointDeliveryExtension.DocumentLibraryProvider,ReportingServicesSharePointDeliveryExtension">
If you want to minimize the noise that error introduces in your log files, simply proceed to comment out that extension from rsreportserver.config. To do so, the existing element should be modified appending the characters higlighted below:
<!--Extension Name="Report Server DocumentLibrary" Type="Microsoft.ReportingServices.SharePoint.SharePointDeliveryExtension.DocumentLibraryProvider,ReportingServicesSharePointDeliveryExtension"-->
As you can find out for yourself if you reflect the code of the static constructor of the class implementing that delivery extension, it throws just that exception when SSRS is not installed in SharePoint integrated mode.