PowerShell to Audit GPO's

I have recently taken ownership of an AD domain.  The domain had previously been managed by numerous people, all with differing approaches, resulting in extremely varied GPO application across the domain.  Each server is in it's own OU.  Some have GPO's applied, some do not.  I am currently only worried about servers (mainly 2008 but I digress).  I also have System Center configured (which I plan to use in this process).

I created a Powershell script to create an HTML GPO report.   My issue - I am using the Get-GPResultantSetOf cmdlet to gather GPResults.  This will fail if the user account I am running the script under has not ran a "gpresult /r" from that server.  As I am a new admin, I have certainly not done this (and I would like fresh data).

So I added the line:

Invoke-Command -ScriptBlock {GPResult /r} -ComputerName $Computer

But this seems to fail due to... security policies (applied by the  very GPO's I am trying to audit!).  Here's the error:

PS WNP:\> WC-GPAudit -CollectionName WC-test
[SERVERNAME] Connecting to remote server SERVERNAME failed with the following error message : WinRM cannot complete the operation. Verify that the specified 
computer name is valid, that the computer is accessible over the network, and that a firewall exception for the WinRM service is enabled and allows access from this 
computer. By default, the WinRM firewall exception for public profiles limits access to remote computers within the same local subnet. For more information, see the 
about_Remote_Troubleshooting Help topic.
    + CategoryInfo          : OpenError: (SERVERNAME:String) [], PSRemotingTransportException
    + FullyQualifiedErrorId : WinRMOperationTimeout,PSSessionStateBroken

Select allOpen in new window

And the PowerShell Script:

function WC-GPAudit{
Param (          
            [Parameter(Mandatory=$False)]
            [String]$CollectionName,

            [Parameter(Mandatory=$False)]
            [String[]]$ComputerName
)

Import-Module GroupPolicy

If ((![string]::IsNullOrEmpty($CollectionName)) -and ([string]::IsNullOrEmpty($ComputerName))) {

    Import-Module ((Split-Path $env:SMS_ADMIN_UI_PATH)+"\ConfigurationManager.psd1")
    Set-Location -Path WNP:
    $CollectionID = Get-CMDeviceCollection -Name $CollectionName | Select CollectionID
    $ComputerList = (Get-CMDevice -CollectionId $CollectionID.CollectionID).Name

}

If ((![string]::IsNullOrEmpty($ComputerName)) -and ([string]::IsNullOrEmpty($CollectionName)))  {

    $ComputerList = $ComputerName

}

ForEach ($Computer in $ComputerList){
    Invoke-Command -ScriptBlock {GPResult /r} -ComputerName $Computer 
    Get-GPResultantSetOfPolicy -Path c:\Temp\Report\$Computer.html -ReportType HTML -Computer $Computer
    }
}

Select allOpen in new window

Any ideas of how I could get the RSoP?