diff --git a/src/main/java/org/dynmap/MapManager.java b/src/main/java/org/dynmap/MapManager.java
index bac167c0..73c00a18 100644
--- a/src/main/java/org/dynmap/MapManager.java
+++ b/src/main/java/org/dynmap/MapManager.java
@@ -99,6 +99,7 @@ public class MapManager extends Thread {
 	/* initialize and start map manager */
 	public void startManager()
 	{
+		synchronized(lock) {
 		running = true;
 		this.start();
 		try {
@@ -107,56 +108,63 @@ public class MapManager extends Thread {
 		} catch(SecurityException e) {
 			log.info("Failed to set minimum priority for worker thread!");
 		}
+		}
 	}
 
 	/* stop map manager */
 	public void stopManager()
 	{
-		if(!running)
-			return;
-
-		log.info("Stopping map renderer...");
-		running = false;
-
-		try {
-			this.join();
-		} catch(InterruptedException e) {
-			log.info("Waiting for map renderer to stop is interrupted");
+		synchronized(lock) {
+			if(!running)
+				return;
+	
+			log.info("Stopping map renderer...");
+			running = false;
+	
+			try {
+				this.join();
+			} catch(InterruptedException e) {
+				log.info("Waiting for map renderer to stop is interrupted");
+			}
 		}
 	}
 
 	/* the worker/renderer thread */
 	public void run()
 	{
-		log.info("Map renderer has started.");
-
-		while(running) {
-			boolean found = false;
-
-			MapTile t = staleQueue.popStaleTile();
-			if(t != null) {
-				debugger.debug("rendering tile " + t + "...");
-				t.getMap().render(t);
-
-				staleQueue.onTileUpdated(t);
-
-				try {
-					this.sleep(renderWait);
-				} catch(InterruptedException e) {
+		try {
+			log.info("Map renderer has started.");
+	
+			while(running) {
+				boolean found = false;
+	
+				MapTile t = staleQueue.popStaleTile();
+				if(t != null) {
+					debugger.debug("rendering tile " + t + "...");
+					t.getMap().render(t);
+	
+					staleQueue.onTileUpdated(t);
+	
+					try {
+						Thread.sleep(renderWait);
+					} catch(InterruptedException e) {
+					}
+	
+					found = true;
 				}
-
-				found = true;
-			}
-
-			if(!found) {
-				try {
-					this.sleep(500);
-				} catch(InterruptedException e) {
+	
+				if(!found) {
+					try {
+						Thread.sleep(500);
+					} catch(InterruptedException e) {
+					}
 				}
 			}
+	
+			log.info("Map renderer has stopped.");
+		} catch(Exception ex) {
+			debugger.error("Exception on rendering-thread: " + ex.toString());
 		}
-
-		log.info("Map renderer has stopped.");
 	}
 
 	public void touch(int x, int y, int z) {
diff --git a/src/main/java/org/dynmap/WebServer.java b/src/main/java/org/dynmap/WebServer.java
index 280148ff..2b6c9b82 100644
--- a/src/main/java/org/dynmap/WebServer.java
+++ b/src/main/java/org/dynmap/WebServer.java
@@ -34,18 +34,22 @@ public class WebServer extends Thread {
 
 	public void run()
 	{
-		while (running) {
-			try {
-				Socket socket = sock.accept();
-				WebServerRequest requestThread = new WebServerRequest(socket, mgr, server, debugger);
-				requestThread.start();
-			}
-			catch (IOException e) {
-				log.info("map WebServer.run() stops with IOException");
-				break;
+		try {
+			while (running) {
+				try {
+					Socket socket = sock.accept();
+					WebServerRequest requestThread = new WebServerRequest(socket, mgr, server, debugger);
+					requestThread.start();
+				}
+				catch (IOException e) {
+					log.info("map WebServer.run() stops with IOException");
+					break;
+				}
 			}
+			log.info("map WebServer run() exiting");
+		} catch (Exception ex) {
+			debugger.error("Exception on WebServer-thread: " + ex.toString());
 		}
-		log.info("map WebServer run() exiting");
 	}
 
 	public void shutdown()
diff --git a/src/main/java/org/dynmap/WebServerRequest.java b/src/main/java/org/dynmap/WebServerRequest.java
index fac0922c..4f93cc9c 100644
--- a/src/main/java/org/dynmap/WebServerRequest.java
+++ b/src/main/java/org/dynmap/WebServerRequest.java
@@ -94,6 +94,9 @@ public class WebServerRequest extends Thread {
 				}
 			}
 		}
+		catch(Exception ex) {
+			debugger.error("Exception on WebRequest-thread: " + ex.toString());
+		}
 	}
 	
 	public void handleUp(BufferedOutputStream out, String path) throws IOException {
diff --git a/src/main/java/org/dynmap/debug/BukkitPlayerDebugger.java b/src/main/java/org/dynmap/debug/BukkitPlayerDebugger.java
index 80b3fb70..866ad4e5 100644
--- a/src/main/java/org/dynmap/debug/BukkitPlayerDebugger.java
+++ b/src/main/java/org/dynmap/debug/BukkitPlayerDebugger.java
@@ -34,45 +34,45 @@ public class BukkitPlayerDebugger implements Debugger {
 		prepend = pdfFile.getName() + ": ";
 	}
 	
-	public void enable() {
+	public synchronized void enable() {
 		plugin.getServer().getPluginManager().registerEvent(Event.Type.PLAYER_COMMAND, new CommandListener(), Priority.Normal, plugin);
 		plugin.getServer().getPluginManager().registerEvent(Event.Type.PLAYER_QUIT, new CommandListener(), Priority.Normal, plugin);
 		log.info("Debugger enabled, use: " + debugCommand);
 	}
 	
-	public void disable() {
+	public synchronized void disable() {
 		clearDebugees();
 	}
 	
-	public void addDebugee(Player p) {
+	public synchronized void addDebugee(Player p) {
 		debugees.add(p);
 	}
 	
-	public void removeDebugee(Player p) {
+	public synchronized void removeDebugee(Player p) {
 		debugees.remove(p);
 	}
 	
-	public void clearDebugees() {
+	public synchronized void clearDebugees() {
 		debugees.clear();
 	}
 	
-	public void sendToDebuggees(String message) {
+	public synchronized void sendToDebuggees(String message) {
 		for (Player p : debugees) {
 			p.sendMessage(prepend + message);
 		}
 	}
 	
-	public void debug(String message) {
+	public synchronized void debug(String message) {
 		sendToDebuggees(message);
 		if (isLogging) log.info(prepend + message);
 	}
 	
-	public void error(String message) {
+	public synchronized void error(String message) {
 		sendToDebuggees(prepend + ChatColor.RED + message);
 		if (isLogging) log.log(Level.SEVERE, prepend + message);
 	}
 	
-	public void error(String message, Throwable thrown) {
+	public synchronized void error(String message, Throwable thrown) {
 		sendToDebuggees(prepend + ChatColor.RED + message);
 		sendToDebuggees(thrown.toString());
 		if (isLogging) log.log(Level.SEVERE, prepend + message);
diff --git a/src/main/java/org/dynmap/kzedmap/DefaultTileRenderer.java b/src/main/java/org/dynmap/kzedmap/DefaultTileRenderer.java
index ba44f350..81eb3546 100644
--- a/src/main/java/org/dynmap/kzedmap/DefaultTileRenderer.java
+++ b/src/main/java/org/dynmap/kzedmap/DefaultTileRenderer.java
@@ -13,6 +13,8 @@ import java.util.logging.Logger;
 
 import javax.imageio.ImageIO;
 
+import org.bukkit.Block;
+import org.bukkit.Chunk;
 import org.bukkit.World;
 import org.dynmap.MapManager;
 import org.dynmap.MapTile;
@@ -40,6 +42,21 @@ public class DefaultTileRenderer implements MapTileRenderer {
 		int ix = tile.mx;
 		int iy = tile.my;
 		int iz = tile.mz;
+		
+		Block block = tile.getMap().getWorld().getBlockAt(ix, iy, iz);
+		if (block == null) {
+			debugger.debug("Could not get block for rendering.");
+			return;
+		}
+		Chunk chunk = block.getChunk();
+		if (chunk == null) {
+			debugger.debug("Could not get chunk for rendering.");
+			return;
+		}
+		if (!world.isChunkLoaded(chunk)) {
+			debugger.debug("Chunk was not loaded, but we'll still continue render.");
+		}
+		
 		int jx, jz;
 
 		int x, y;