Do you have an ASP upload component installed on your servers ?
Yes, ASPUpload is installed. This is an Active Server component which enables an ASP application to accept, save and manipulate files uploaded with a browser. The files are uploaded via an HTML POST form with one or more <INPUT TYPE=FILE> tags. The <FORM> tag must contain the attribute ENCTYPE="multipart/form-data"
Further information can be found at the ASP Upload site