Yes, in many cases, you do need upload processing software like FileUp on the server when uploading files with JFile. JFile is an HTTP client, which posts files (and/or form elements) to a server, in compliance with the HTTP file transfer protocol. There must also be software on the server which can process the upload in compliance with this protocol.
JFile sends multipart/form-data encoded HTTP request to the server. Multipart/form-data encoding is an Internet standard (specified in RFC 1867) for sending different types of information over the Internet as one bundle. If you are uploading to a classic ASP application on a Windows server, the standard form components ASP supplies for web serving do not support multipart/form-data encoding. This means you have to use a third-party product such as FileUp to do it for you. If you are uploading to an ASP.NET application, there is some built-in upload processing capability, but it is limited to small files (our upcoming FileUp Enterprise Edition will provide unlimited, industrial-grade file transfer capability in a .NET environment). If you are uploading to a Unix/Linux server, uploads can be handled in various ways in server-side code, with or without third party software.