Account Creation Error

I am getting this error after I create the accounts:

Method invocation failed because [System.Object[]] doesn't contain a method nam
ed 'replace'.
At C:\Users\XXXXX\Desktop\PoGoMap-GUI\PokemonGo-Map\usernamescsv.ps1:39 char:40

•     $usernames = $usernames.replace <<<< ($username,("ptc," + $username))
  

  • CategoryInfo : InvalidOperation: (replace:String) [], RuntimeEx
    ception
  • FullyQualifiedErrorId : MethodNotFound