I didn't know if there were any difference between a crash report while on a server or in singleplayer, so I took both. This link is for Singleplayer :
http://www.mediafire.com/?dzv7omepndw5j54
Multiplayer :
http://www.mediafire.com/?rbz0f38adm99irn
And in fact the bug doesn't seems to happens only near the spawn. I've changed it and I still got this.
I thought that too, but I've tried in singleplayer and that's the same
This is not spawn protection, because I've put only one in the server.properties, and also because I can still break or place blocs. A friend of mine have the same bug on this world, but I can't figure out if this affect only this world in particular
(sorry if my grammar/english is bad)
Okay, so I've made a new map, and the bug is still there. I've re-installed minecraft, made a new map and the bug disappeared. So it means my map has a bug. I don't know if this is a general bug that can happen to anybody, but if anyone has any solution, please tell me.
EDIT : After many tries and manipulation, the map works well in singleplayer, but my server seems overloaded (he wasn't before). My computer is really slow, so that would explain all.
Sorry for inconvenient, this can now be closed.