Epikos1994

I don't understand what version you are using, an old map on a new server?

Any info on why the essentials plugin did not work... Because I dont know any other way of adding it without using a different plugin.

Why dont you just revert back to the old version?

With the update some mods have removed certain items, etc... or changed said names hence the reason you cant find them

(This isnt a solution more like a helpline) The Problem seems to be serverside... maybe the rented server doesnt support mods, or if so maybe a vital mod like forge isnt installed properly, try reinstalling the server from scratch then try to incorporate the old server bit by bit and that should pinpoint any problems, also to your problem of converting classic to lite, try using a map editor to copy vital chunks (buildings, factorys... etc) and replace old mods parts (condensors... etc) with a random block (dirt,gravel...) , dont use the entirety of the map because then some materials wont generate causing problems for the players. Also, Check out this guide to help you convert... http://forums.technicpack.net/threads/how-to-convert-tekkit-classic-world-to-tekkit-lite.34915/