chunks randomly regenerated at all map

Need help on bukkiti 1.1

chunks randomly regenerated at all map.
Suddenly, regenerated a chunk of badrock and nether black and somtime the things we have built over then comes the dirt

Think i get answared here: http://forums.bukkit.org/threads/fi...-lag-causes-on-your-server-1769.36986/page-76

EDIT by Moderator: merged posts, please use the edit button instead of double posting.