You are going to need to provide some information about what you actually did. Ideally with a log of what the computer told you in return. The guide could be 100% correct, and still you might get an error at the end. Please note I'm not referring to your linux skills, but rather, that is a looong guide and to err is human. There are many pitfalls and gotchas along the way. The first being that it was only tested to work with Ubuntu up to version 14.10... that doesn't mean it won't work, but it does mean that your actions and the computers reactions are crucial in determining what in fact is wrong.
Please never EVER download and run a script like these guys tell you without making sure you understand exactly what it does.
Besides I find this tutorial quite tedious, with too many opportunities to fuck up... I know you're probably not looking for yet another way to setup this up, but here's how I did anyway :
Have a look at transmission-daemon (present in the default repositories) sudo apt-get install transmission-daemon. Once installed, edit /etc/transmission-daemon/settings.json to configure the remote access (make sure you remove the IP whitelist) and the destination directory for the downloads. Make sure the transmission-daemon service is stopped (sudo service transmission-daemon stop) when editing the configuration file. Otherwise changes will be overwritten when restarting the service. (sudo service transmission-daemon [re]start) Then using your web browser go to http://your-server-ip:9091 to access the remote control interface.
Alternatively you can use a desktop client like transgui to manage your downloads remotely, or Remote Transmission for Android.
To retrieve your files from your server, it depends on how convenient you want things to be. If you just want a fast and secure solution, just use SFTP. Otherwise you can use a web file manager called Pydio. It requires a webserver + PHP : sudo apt-get install apache2 libapache2-mod-php5. If you don't plan using your webserver for anything else, just unzip the archive straight into /var/www as root and go to http://your-server-ip to begin the setup process (does NOT require a database).