When I execute the command /port create XXX, the server return this exception:

2012-12-25 02:19:04 [INFO] RodrigoFish issued server command: /port create a
2012-12-25 02:19:04 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'port' in plugin Ports v0.3
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:186)
at org.bukkit.craftbukkit.v1_4_6.CraftServer.dispatchCommand(CraftServer.java:510)
at net.minecraft.server.v1_4_6.PlayerConnection.handleCommand(PlayerConnection.java:980)
at net.minecraft.server.v1_4_6.PlayerConnection.chat(PlayerConnection.java:898)
at net.minecraft.server.v1_4_6.PlayerConnection.a(PlayerConnection.java:853)
at net.minecraft.server.v1_4_6.Packet3Chat.handle(Packet3Chat.java:44)
at net.minecraft.server.v1_4_6.NetworkManager.b(NetworkManager.java:290)
at net.minecraft.server.v1_4_6.PlayerConnection.d(PlayerConnection.java:112)
at net.minecraft.server.v1_4_6.ServerConnection.b(SourceFile:39)
at net.minecraft.server.v1_4_6.DedicatedServerConnection.b(SourceFile:30)
at net.minecraft.server.v1_4_6.MinecraftServer.r(MinecraftServer.java:598)
at net.minecraft.server.v1_4_6.DedicatedServer.r(DedicatedServer.java:224)
at net.minecraft.server.v1_4_6.MinecraftServer.q(MinecraftServer.java:494)
at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:427)
at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NullPointerException
at net.robinjam.bukkit.ports.commands.CreateCommand.onCommand(CreateCommand.java:39)
at net.robinjam.bukkit.util.CommandManager.runCommand(CommandManager.java:74)
at net.robinjam.bukkit.util.CommandManager.onCommand(CommandManager.java:32)
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
... 15 more

You'll need to select the port's activation region using WorldEdit before you use the /port create command. You might find this tutorial helpful.

It shouldn't have thrown an error though; I'll fix that in the next release.