Minecraft – way to add furniture to Minecraft SMP

For a mod to work in multiplayer, the author needs to create a SMP version. The most common way is through bukkit.

However if a mod adds new items, like the two examples you have given, playing SMP with it will require both a server mod and client mod to work together. This usually means the same developer or team needs to make both. If they don't provide both yet add new items, the mod is likely single player only.

For combining several of these mods, they all need to use compatible methods of adding themselves. If one is a bukkit mod while the other is its own mod that conflicts with bukkit you're usually out of luck.

If the biomes shifted it's probably due to a corrupted "seed" (just a long number) which seems to happen quite easily when the server crash. If you have an old save that still is ok you can get the correct seed from that save, and then edit your current save and set the correct seed.

It's really easy to read and set seeds with LolEdit. You just open the save in the editor and modify the seed field.

If you have explored new areas while the seed was corrupted you might also get problems with "sliced walls". Check my slighty longish answer in this thread for a solution to that.