Mods on server aren't working

[Harryoui]

Title: Mods on server aren't working

Version: 3.1.2

OS: macbook pro..

Java Version: java preferences

Description of Problem:

I've made a tekkit server and I have too many items up, the tekkit items are there, but i can't spawn them, it says: theres no items with ID <ID> What have i done wrong in making the server?

Error Messages:

There's no items called <ID>

Error Log:

N/A