Okay so I downloaded this playlist and I basically had the same issue as you before. First you have to make sure that Launchbox is 100% closed meaning check Task Manager to see if "launchbox.exe" is still present and if so kill the process before copying the file over to the playlist folder to prevent it from being deleted. Secondly, between the time this playlist was made and to now, the developers of LaunchBox seemed to have changed the way XML playlists work and added/removed some details. You need to select the drop down box underneath the search bar and select "playlist" where you should find it, then right click and hit "edit," then change the following values I've circled here.