I recently install the Too many items mod and i did everything with the text and enable multilayer and the give command in the text file (/items what ever numbers were there) and yes i am op when i try to give something to my self it says Unknown Material and the item id. please help .
bloodmoon, epicglass, colors, essentials, essentials group manager, tribu, mobarena, worldedit, and snowballnext door
so remove essentials and see for your self after that here is fix http://www.minecraftserverhost.net/secure/knowledgebase.php?action=displayarticle&id=77