can no longer run to invalid targets

src/engine/net/client/handlers/AttackCmdMsgHandler.java

@@ -56,9 +56,12 @@ public class AttackCmdMsgHandler extends AbstractClientMsgHandler {
             case Building:
                 target = BuildingManager.getBuilding(msg.getTargetID());
                 break;
+            case NPC:
+                target = NPC.getNPC(msg.getTargetID());
+                break;
         }
-
         if(target == null) {
+            playerCharacter.setCombatTarget(null);
             return true; // cannot attack a null target
         }
         //set sources target