Minecraft server startup help

My recommended solution for this kind of thing tends to be "Use The System!".

If you have the option, enabling Time Machine from system preferences to create a full disk backup every hour is usually a good idea, and if you don't have the opportunity, you might want to consider getting an external disk and implementing that approach.

If that is completely out of the question for whatever reason, the alternative is using cron.

Setting up the interval running is easy enough, a simple man crontab should give you the information you need on that; but having a script to actually do the backup might be useful:

#!/bin/sh
cd ~/Desktop/MinecraftServer # or the path to your minecraft server directory
rm -rf world.bak
cp -r world world.bak

Save this as a "minecraft_server_backup.sh" and chmod +x it.

This particular script only keeps the most recent backup, and additionally, it doesn't actually check if the server is running before making a backup.

You have to rename the downloaded craftbukkit file from

craftbukkit-1.x.x-xx.x.jar

to

craftbukkit.jar

The .bat command expects a file called craftbukkit.jar, if it doesn't find it, you get that error.

Also check what @SevenSidedDie said.