Need more information:
[ol]
[li]Show us your source code that handles the FTP transaction, including which line generates the error[/li]
[li]What sort of error is it? A returned value from your TIdFTP component, or an exception?[/li]
[li]Have you tried connecting using a proper FTP client program? Does it do what you're trying to do in your code without any problem?[/li]
[/ol]