Bah, now with less muppetry.

Silly typo.

src/me/ryanhamshire/GriefPrevention/GriefPrevention.java

@@ -2402,7 +2402,7 @@ public class GriefPrevention extends JavaPlugin
                         // First off, you cannot siege yourself, that's just
                         // silly:
                         if (attacker.getName().equals( defender.getName() )) {
-                            GriefPrevention.sendMessage(player, TextMode.Err, Messages,NoSiegeYourself);
+                            GriefPrevention.sendMessage(player, TextMode.Err, Messages.NoSiegeYourself);
                             return true;
                         }