If you have done a single server install with AD and hit this error:
An error has occurred during report processing. (rsProcessingAborted)Cannot impersonate user for data source 'TfsReportDS'. (rsErrorImpersonatingUser)Logon failed. (rsLogonFailed)Logon failure: the user has not been granted the requested logon type at this computer. (Exception from HRESULT: 0x80070569)
Go to the local security policy and give the service account (TFSSERVICE) permissions to logon locally. Reboot and you should be golden.