Remove-VM error

Hi Guys,

I'm new to PowerCLI and I'm trying to run a simple command and seeing the below message after connecting to the ESXi server

PowerCLI C:\Program Files (x86)\VMware\Infrastructure\vSphere PowerCLI> Get-VM VM_guest | Remove-VM -DeletePermanently -Confirm:$false
Remove-VM : 4/22/2013 2:02:44 PM    Remove-VM        fault.RestrictedVersion.summary
At line:1 char:26
+ Get-VM VM_guest| Remove-VM <<<<  -DeletePermanently -Confirm:$false
+ CategoryInfo          : NotSpecified: (:) [Remove-VM], RestrictedVersion
+ FullyQualifiedErrorId : Client20_MoServiceImpl_Remove_SingleObject_ViError,VMware.VimAutomation.ViCore.Cmdlets.Commands.RemoveVM

Want to know the cause of the issue.

Thanks in advance.