When you remove a object, the paths attacked to it will be removed to

src/gui/simulator/DrawEngine.java

@@ -107,6 +107,7 @@ public abstract class DrawEngine {
 
     public void remove(){
         this.terrain.getEntities().remove(this);
+        this.terrain.removeWalkingPaths(this);
     }
 
 

src/gui/simulator/Terrain.java

@@ -501,5 +501,10 @@ public class Terrain extends JPanel {
 	public int getMaxVisitors(){
 		return maxvisitors;
 	}
+	public void removeWalkingPaths(DrawEngine object){
+		for(WalkingPath p:paths.getWalkingPadObject(object)){
+			paths.remove(p);
+		}
+	}
 	
 }