Weird glitch with mod

Hello. After installing the mod i noticed whenever I find a dungeon, all the mobs are nowhere to be found, and items are already on the ground.. (Stacks of ores, swords, etc all just laying out). Also trees have formed into the buildings. This only happens on my server not on single player. So is there a different way to download this mod on the server? Is there a certain folder i need to put the chocolate folder in?