Im not sure if you can, but skripting a tab with luck perms ranks are easy, if you need one, tell me and I will make a tab skript with any skript variable you want and luck perm ranks (if you want them). Also tell me how you want them
For now the only way to join an uploaded world is by setting it to the highest level world.
Go to your server settings, and go to level world then put the name of the world including the ul_
I recommend doing what @CoolProgrammer advised then paste it into pastebin and send the link here. We can check whats going on with your server with the logs.