MCMULTIPLAYERCRASH!

What I expected to happen was...:
I Was Making The Lobby Of My Minecraft Server.
I Was Waiting For the other MC player to come online.

What actually happened was...:
I Crashed! See attached reports.

Steps to Reproduce:
1. Go On My Server.
2. Ask someone to come on to the server.
3. They Ask You For MCPlugins.
4. If You Can, Stop The Server and add a CraftBukkit jar.
5. Add Slimefun Plugin.
6. Wait, Fly Around, etc.
7.Unable to render embedded object: File (**CRASH**) not found.

note: i am not sure if you would help me with plugins, but you can ask
the people at minecraftserver.net.