Problem with EnumKey "Object Not a Collection"

The purpose of this script was to allow me to quickly change the WSUS intranet server (I'm not fully done with it yet), instead of using the local Group Policy. Sometimes the WindowsUpdate key does not exist. Rather than guessing and writing a new one, I'd rather check if it exists, and only write if it doesn't. The problem I've had is I get "Object is not a collection" when I use EnumKey. From what I know, null values are causing the error, but I don't know how to resolve it.

const HKEY_LOCAL_MACHINE = &H80000002
strComputer = "."
Set objReg=GetObject("winmgmts:{impersonationLevel=impersonate}!\\"&_ 
    strComputer & "\root\default:StdRegProv")
strKeyPath = "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows"
Wscript.Echo "This program serves to connect you to your intranet WSUS server. It will create or modify the registry."

objReg.EnumKey HKEY_LOCAL_MACHINE, strKeyPath, arrSubKeys

For Each subkey In arrSubKeys
    bFound = (lcase(subkey) = lcase(regkey))
    if bFound then exit for
Next

if bFound then
  Wscript.echo "'WindowsUpdate' exists."
  'Continue script without creating a key named WindowsUpdate.
  Else
  'Since key did not exist, create key and then continue.