Update: This is caused by by how the particular domain environment was constructed. Read more on http://blogs.technet.com/operationsmgr/archive/2009/01/27/opsmgr-2007-error-running-report-message-loading-reporting-hierarchy-failed-access-is-denied.aspx
After trying to open Reporting from the Ops Console I got the next error:
I checked if Reporting was configured correctly with the Configure Report Server tool.
Checked if SharePoint Integration was enabled. And that wasn’t the case.
Tried to open ReportServer in a Browser.
Restarted the SQL Server Reporting Services (MSSQLSERVER) service. But still no luck.
Opened Configure Report Server tool again and applied the Default Settings for the Report Server Virtual Directory and Report Manager Virtual Directory.
Re-entered the correct password for the Windows Service Identity and clicked Apply.
Now the Web Service Identity failed.
Changed the Web Service Identity for the Report Server and Report Manager from the DefaultAppPool to ReportServer. After the refresh the ASP.NET Service Account changed automatically from NT Authority\NetworkService to CONTOSO\OM_DRA.
Clicked Apply and did a Refresh and that solved it.