FTP is a security intensive protocol and it depends heavily on server settings to determine whether access is allowed to specific directories. Typically file uploads require a specific user log in. Make sure you have all the information to perform operation on the FTP server and when in doubt try a regular FTP client application like Internet Explorer 5.0, WS-FTP or Cute FTP to verify that you have the proper access for the operation.

Specifically pay attention to the following:

• Case of paths and usernames/passwords (especially for Unix servers!)
  
• The direction of slashes. Many Unix servers require forward slashes