Powershell ftp upload error 530 not logged in

I am struggling to get a PowerShell script to work. I am very new to PowerShell so could be missing something stupid.

$sourceuri = "ftp://ftp.example.com/myfolder/myfile.xml"
$username = "user"
$password = "password"

# Create a FTPWebRequest object to handle the connection to the ftp server
$ftprequest = [System.Net.FtpWebRequest]::create($sourceuri)

$credentials = New-Object System.Net.NetworkCredential($username,$password)
# set the request's network credentials for an authenticated connection
$ftprequest.Credentials = $credentials

$ftprequest.Method = [System.Net.WebRequestMethods+Ftp]::UploadFile
$ftprequest.UseBinary = 1
$ftprequest.KeepAlive = 0

# read in the file to upload as a byte array
$content = gc -en byte $fileName
$ftprequest.ContentLength = $content.Length
# get the request stream, and write the bytes into it
$rs = $ftprequest.GetRequestStream()
$rs.Write($content, 0, $content.Length)
# be sure to clean up after ourselves
$rs.Close()
$rs.Dispose()

I get the following error:

Exception calling "GetRequestStream" with "0" argument(s): "The remote server returned an   error: (530) Not logged in."
At C:\temp\copyfile.ps1:63 char:35
+ $rs = $ftprequest.GetRequestStream( <<<< )

I can connect via IE to it easily so thought maybe something else was wrong so did this quickly in C#:

        string filePath = @"C:\temp\myfile.xml";
        string FTPAddress = @"ftp://ftp.example.com/myfolder";
        FtpWebRequest request = (FtpWebRequest)FtpWebRequest.Create(FTPAddress + "/" + Path.GetFileName(filePath));
        request.Method = WebRequestMethods.Ftp.UploadFile;
        string username = "user";
        string password = "password";
        request.Credentials = new NetworkCredential(username, password);
        request.UsePassive = true;
        request.UseBinary = true;
        request.KeepAlive = false;

        FileInfo file = new FileInfo(filePath);