How to get an apppool with Get-Item in powershell?

I have try the following command but always receve an COM error.

PS E:\WebSites> Get-Item "IIS:\AppPools\Rhino.Trunk"

Get-Item : Cannot retrieve the dynamic parameters for the cmdlet. Unable to cast COM object of type
'Microsoft.IIs.PowerShell.Framework.AppHostQueryProcessor' to interface type
'Microsoft.IIs.PowerShell.Framework.IAppHostQueryProcessor'. This operation failed because the QueryInterface call on
the COM component for the interface with IID '{6E0E6BE3-71C1-4A66-800E-11B9CBA00EAB}' failed due to the following
error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).
At line:1 char:1
+ Get-Item "IIS:\AppPools\Rhino.Trunk"
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Get-Item], ParameterBindingException
    + FullyQualifiedErrorId : GetDynamicParametersException,Microsoft.PowerShell.Commands.GetItemCommand

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