Hi there @ureuipoa,
I suggest resetting the world (as you tried to load a world made in a newer version on a older version) by going to "File Manager" and deleting the folders "world", "world_nether" and "world_the_end" (when the server isn't online) and try to start up the server.
Also, install "Essentials" and "Vault" as some of your plugins require them to operate.
Additionally, delete "lifesteal-smp-plugin-1.6.4.0.jar" as that plugin seems to be broken/causing errors in your console.
If this didn't help, contact support here then click on "Contact Support" on that page and explain the issue.