Backup Sharepoint 2010 (с использованием Powershell - Backup-SPFarm)

Я спросил об этом на ServerFault, но не получил никакого ответа, я знаю, что это командная строка, VERBOSE OUTPUT

PS E:\Backups\Script> Backup-SPFarm -Directory E:\Backups -BackupMethod Full -Verbose
VERBOSE: Leaving BeginProcessing Method of Backup-SPFarm.
VERBOSE: Performing operation "Backup-SPFarm" on Target "SHAREPOINTSERV".
Backup-SPFarm : Object reference not set to an instance of an object.
At line:1 char:14
+ Backup-SPFarm <<<<  -Directory E:\Backups -BackupMethod Full -Verbose
    + CategoryInfo          : InvalidData: (Microsoft.Share...mdletBackupFarm:SPCmdletBackupFarm) [Backup-SPFarm], NullReferenceException
    + FullyQualifiedErrorId : Microsoft.SharePoint.PowerShell.SPCmdletBackupFarm


VERBOSE: Leaving ProcessRecord Method of Backup-SPFarm.
VERBOSE: Leaving EndProcessing Method of Backup-SPFarm.