VLC Remote uses Bonjour to look for other computers on the network.
Unfortunately, no technique for scanning the network is foolproof as there are lots of ways that computers can be set to hide themseleves!
Here are two simple things you can try.
While the setup helper is running, it will make sure that there is a Bonjour service advertised from your computer.
Click scan again (the icon that looks like a satellite dish) to search the network.
If you can see your computer now, then click on the 'Add computers' button to add this computer to the saved list.
You can safely quit the VLC helper now, and as the computer details are saved, you won't need it running to make a connection in the future.
The VLC Setup helper has a 'Show My IP Address' button.
Click on this to find the IP address of your computer
You can then enter the IP address manually (click on the 'Add Computer' button again).
Still not working?
There is extensive help at the Hobbyist Website. Just click through to www.HobbyistSoftware.com/VLC
Then check that you have followed the setup instructions, and try the troubleshooting instructions that follow.