How to create an ubuntu server on old computer?

[alabasterfox]

Im following this project on how to build a Linux Web Server Computer and I'm almost done! But when I try to allow sharing on my www folder ubuntu says that "Sharing service is not installed: You need to install the Windows networks sharing service in order to share you folders". When i select "Install service" It directs me to install something called "samba" but then immediately says "Can not install 'samba' (E:Unable to correct problems, ou have held broken packages.)" How can I fix whatever's going on so I can share this folder and finish this server set up? I'm like right there at the end >.<

Link to project:
How To Build a Linux Web Server With An Old Computer [Part 2]