$ftp = "ftp://192.168.0.2/"
$user = "user"
$pass = "pass"
$webclient = New-Object System.Net.WebClient
$webclient.Credentials = New-Object System.Net.NetworkCredential($user,$pass)
$item="C:/Pruebas/origen/prueba.txt"
$uri = New-Object System.Uri($ftp+$item.Name)
$webclient.UploadFile($uri, $item.FullName)

Excepción al llamar a "UploadFile" con los argumentos "2": "Excepción durante una solicitud WebClient."
En línea: 8 Carácter: 1
+ $webclient.UploadFile($uri, $item.FullName)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : WebException