I am starting to see this error on many newly created Windows 2008 R2 SP1 domain controllers:
The WinRM service failed to create the following SPNs the event id is 10154
The solution is to find the domain controller in Active Directory Users and Computers.
Select Advanced Features and right click and select Properties on the DC with the error.
Select the Security tab and click on the Advanced button.
Select Add and enter the name NETWORK SERVICE.
Change the Apply to so that This object only is selected and allow the Validated write to service principal name right.
Now use the OK button all the way back.
The last thing we need to do is to restart the Windows Remote Management service and the error is no longer shown in the event log.