2011-10-31 00:07:51 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'port' in plugin Ports v0.1.1
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:42)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:163)
at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:355)
at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:757)
at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:722)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:715)
at net.minecraft.server.Packet3Chat.a(Packet3Chat.java:33)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:226)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:92)
at net.minecraft.server.NetworkListenThread.a(SourceFile:108)
at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:471)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)
Caused by: javax.persistence.OptimisticLockException: Data has changed. updated [0] rows sql[update port set destination_id=? where id=? and name=? and description=? and x1=? and y1=? and z1=? and x2=? and y2=? and z2=? and world=? and x=? and y=? and z=? and yaw=? and pitch=? and destination_id=? and departure_schedule=?] bind[null]
at com.avaje.ebeaninternal.server.persist.dml.DmlHandler.checkRowCount(DmlHandler.java:123)
at com.avaje.ebeaninternal.server.persist.dml.UpdateHandler.execute(UpdateHandler.java:106)
at com.avaje.ebeaninternal.server.persist.dml.DmlBeanPersister.execute(DmlBeanPersister.java:105)
at com.avaje.ebeaninternal.server.persist.dml.DmlBeanPersister.update(DmlBeanPersister.java:85)
at com.avaje.ebeaninternal.server.persist.DefaultPersistExecute.executeUpdateBean(DefaultPersistExecute.java:110)
at com.avaje.ebeaninternal.server.core.PersistRequestBean.executeNow(PersistRequestBean.java:531)
at com.avaje.ebeaninternal.server.core.PersistRequestBean.executeOrQueue(PersistRequestBean.java:557)
at com.avaje.ebeaninternal.server.persist.DefaultPersister.update(DefaultPersister.java:430)
at com.avaje.ebeaninternal.server.persist.DefaultPersister.forceUpdate(DefaultPersister.java:203)
at com.avaje.ebeaninternal.server.core.DefaultServer.update(DefaultServer.java:1615)
at com.avaje.ebeaninternal.server.core.DefaultServer.update(DefaultServer.java:1605)
at com.avaje.ebeaninternal.server.core.DefaultServer.update(DefaultServer.java:1584)
at net.robinjam.bukkit.ports.commands.LinkCommand.onCommand(LinkCommand.java:40)
at net.robinjam.bukkit.util.CommandManager.onCommand(CommandManager.java:26)
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:40)
... 12 more

This is (hopefully) fixed in master and will be fixed in v0.2. If this issue pops up again in the future, please feel free to re-open it, but remember to include a copy of your bukkit.yml file.