from tonka: sorry to hear that, but you just unzip it inside the plugins folder, its easy so i cannot explain it any more simple than this, maybe read around to find out how to install plugins.
my server support has the plugin working after a fashion. But the hot key shift L does not work. So of course I cannot claim land.
The way they got it working was to put the plugin jar file should be inside a folder with the same name. \Plugins\MyPlugin\MyPlugin.jar.
HOWEVER I now have two folders. One saying land claim with a folder called my world and in that folder the 3 databases. The other folder Says World protection with my world name in it and 3 databases in it.