productkey

hello,

I have problem with powershell (x86). In the Web i found a script witch can show me my windows 7 product key, because i lost a cd with this number. And when i using this script i get one of the this error only number is diferent, while for others it has helped.... maybe you can help me :-)

this is a error:

cannot index into a null array.
at c:\users\romas\deskot\getproductkey.ps1: 19 char:47
+$k = $k*256 -bxor $binarray[ <<<< $j]
+categoryinfo :invalidoperation: (0:int32) [], runtimeexception
+fullyqualifiederrorid: nullarray.

and second error in the same time is:

cannot index into a null array.
at c:\users\romas\deskot\getproductkey.ps1: 20 char:27
+$binarray[ <<<<$j] = [math]]::truncate{$k/24)
+categoryinfo :invalidoperation: (0:int32) [], runtimeexception
+fullyqualifiederrorid: nullarray

this is a script:

function Get-WindowsKey {
    ## function to retrieve the Windows Product Key from any PC
    ## by Jakob Bindslet (jakob@bindslet.dk)
    param ($targets = ".")
    $hklm = 2147483650
    $regPath = "Software\Microsoft\Windows NT\CurrentVersion"
    $regValue = "DigitalProductId"
    Foreach ($target in $targets) {
        $productKey = $null
        $win32os = $null
        $wmi = [WMIClass]"\\$target\root\default:stdRegProv"
        $data = $wmi.GetBinaryValue($hklm,$regPath,$regValue)
        $binArray = ($data.uValue)[52..66]
        $charsArray = "B","C","D","F","G","H","J","K","M","P","Q","R","T","V","W","X","Y","2","3","4","6","7","8","9"
        ## decrypt base24 encoded binary data
        For ($i = 24; $i -ge 0; $i--) {
            $k = 0
            For ($j = 14; $j -ge 0; $j--) {
                $k = $k * 256 -bxor $binArray[$j]
                $binArray[$j] = [math]::truncate($k / 24)
                $k = $k % 24
            }
            $productKey = $charsArray[$k] + $productKey
            If (($i % 5 -eq 0) -and ($i -ne 0)) {
                $productKey = "-" + $productKey
            }
        }
        $win32os = Get-WmiObject Win32_OperatingSystem -computer $target
        $obj = New-Object Object
        $obj | Add-Member Noteproperty Computer -value $target
        $obj | Add-Member Noteproperty Caption -value $win32os.Caption
        $obj | Add-Member Noteproperty CSDVersion -value $win32os.CSDVersion
        $obj | Add-Member Noteproperty OSArch -value $win32os.OSArchitecture
        $obj | Add-Member Noteproperty BuildNumber -value $win32os.BuildNumber
        $obj | Add-Member Noteproperty RegisteredTo -value $win32os.RegisteredUser
        $obj | Add-Member Noteproperty ProductID -value $win32os.SerialNumber
        $obj | Add-Member Noteproperty ProductKey -value $productkey
        $obj
    }
}
this is a link where i found this: http://winaero.com/blog/how-to-get-the-windows-product-key-without-using-third-party-software/#comment-952