Not speaking for Jorpho of course but I think you have to email the admin. and tell them what you have and they will send you a special link/info' for uploading.
Yeah that's what I did. Once you get the email back with username and password, get an FTP program if you don't have one (Filezilla is good, google it), then login to their ftp server with it and upload.
BTW, I just uploaded missing game 22173, The Neverhood. Unlike the older game, this has the entire game, including the music and audio. Hopefully they'll let us keep it archived this way...Disk space isn't a problem these days, but I know bandwidth costs are still a bitch.
The game installs and runs fine under my XP system.