I need help. My server is hamachi, and whenever I run Vannilla anyone can join. But if I run Bukkit, nobody can join. It's not any of the plugins. Help? No, it isn't cracked. I just can't run public servers. I might be able to soon, if I can figure it out. EDIT by Moderator: merged posts, please use the edit button instead of double posting.
Its your Windows firewall. You haven't forwarded the port 25565, you forwarded the application (minecraft_server.jar). This is why it broke when moving from vanilla to Bukkit.
You can always turn on Windows firewall logging and see. Do you see connection attempts in your server.log?
Yeah. I just went to my firewall and allowed Minecraft_Server.exe to communicate and stuff. How do I do it so it'll allow Bukkit?
A common mistake people are making could be your server error as well. In the server.properties file, make sure nothing is next the the {server ip=} section. Otherwise, players will not be able to join. I hope I was of some help, Symbiosis