Be careful when registering commands. It shouldn't break the plugin.

Found an error report in the wild suggesting that getCommand() might
occationally fail (if plugin.yml isn't loaded properly, maybe) and
return NULL instead.

Since the commands are only for administrators and plugin authors, 
we'll simply ignore it if this occurs.

ProtocolLib/src/main/java/com/comphenix/protocol/ProtocolLibrary.java

@@ -23,6 +23,8 @@ import java.util.logging.LogRecord;
 import java.util.logging.Logger;
 
 import org.bukkit.Server;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.PluginCommand;
 import org.bukkit.plugin.PluginManager;
 import org.bukkit.plugin.java.JavaPlugin;
 
@@ -187,8 +189,8 @@ public class ProtocolLibrary extends JavaPlugin {
 			}
 			
 			// Set up command handlers
-			getCommand(CommandProtocol.NAME).setExecutor(commandProtocol);
-			getCommand(CommandPacket.NAME).setExecutor(commandPacket);
+			registerCommand(CommandProtocol.NAME, commandProtocol);
+			registerCommand(CommandPacket.NAME, commandPacket);
 	
 			// Notify server managers of incompatible plugins
 			checkForIncompatibility(manager);
@@ -217,6 +219,24 @@ public class ProtocolLibrary extends JavaPlugin {
 			reporter.reportDetailed(this, "Metrics cannot be enabled. Incompatible Bukkit version.", e, statistisc);
 		}
 	}
+
+	private void registerCommand(String name, CommandExecutor executor) {
+		try {
+			if (executor == null) 
+				throw new RuntimeException("Executor was NULL.");
+			
+			PluginCommand command = getCommand(name);
+			
+			// Try to load the command
+			if (command != null)
+				command.setExecutor(executor);
+			else
+				throw new RuntimeException("plugin.yml might be corrupt.");
+		
+		} catch (RuntimeException e) {
+			reporter.reportWarning(this, "Cannot register command " + name + ": " + e.getMessage());
+		}
+	}
 	
 	/**
 	 * Disable the current plugin.