move mail to a pst

I don't know if I am in the right place but here goes

I found this script on the goolge to move emails in Outlook to a PST.  I get an error and I am clueless on how to get to to work. Here is the script.  Any help will be great. 

[Reflection.Assembly]::LoadWithPartialname("Microsoft.Office.Interop.Outlook") | out-null

$olFolders = "Microsoft.Office.Interop.Outlook.OlDefaultFolders" -as [type]

$OlClass = "Microsoft.Office.Interop.Outlook.OlObjectClass" -as [type]

$OlSaveAs = "Microsoft.Office.Interop.Outlook.OlSaveAsType" -as [type]

$OlBodyFormat = "Microsoft.Office.Interop.Outlook.OlBodyFormat" -as [type]

$Outlook = new-object -comobject outlook.application

$NameSpace = $Outlook.GetNameSpace("MAPI")

[ENUM]::GetNames($olFolders)

$NameSpace.Folders | Select Name

$Source = $NameSpace.Folders["myemail@email.com"].Folders.Item("Inbox")

$Messages = $Source.Items | Where-Object {$_.SenderName -eq "john smith"}

$PST = $NameSpace.Folders["Test.pst"].Folders.Item("test")

foreach ($msg in $Messages) {

    "Moving $($msg.Subject) from $($msg.SenderName) sent on $($msg.SentOn) to the PST file."

   $msg.Move($PST)

}