We upgraded to 6.3 and cannot get reporting to work correctly, we are now getting the following error when we run reports:

There was an error generating your report. Please refer to item 468336289780371 for additional diagnostic information. There was an error
during the render phase of the report generation. There was an error generating the document Patch Status There was an error generating the document Patch Status
System.Web.Services.Protocols.SoapException: The permissions granted to user 'domain\username'
are insufficient for performing this operation. --->
Microsoft.ReportingServices.Diagnostics.Utilities.AccessDeniedException: The
permissions granted to user 'domain\username' are insufficient for
performing this operation. at Microsoft.ReportingServices.WebServer.ReportExecution2005Impl.LoadReportDefinition(Byte[]
Definition, ExecutionInfo2& executionInfo, Warning[]& warnings) at
Microsoft.ReportingServices.WebServer.ReportExecutionService.LoadReportDefinition(Byte[]
Definition, ExecutionInfo& executionInfo, Warning[]& warnings)

 

What can we do to resolve this error?