I need help with a problem in the chat

When I chat, there's a (0) in front of my name...It looks like this:
[L](0)NighT3X>Hi
For world managment I am using Multiverse and Multiworld.I removed all the Essentials plugins (Chat,Core,GM) and nothing happens.I am also using ChatColor and BroadCast,PlotMe and more non-chat related plugins.Please help me