[1.7.2] Armor Prefix Server crash

Hi, I made a mod that works fine in client but when I load it in a Cauldron Server It crashes, I looked at the crash report and I think the problem is the armor prefix

Here's the crash report:

http://pastebin.com/hXkSpET9

and here's my mod's main class:

http://pastebin.com/SZbMFnkv

Please help guys