fixed NPC interaction

src/engine/gameManager/BuildingManager.java

@@ -438,7 +438,7 @@ public enum BuildingManager {
 
     public static boolean IsPlayerHostile(Building building, PlayerCharacter player) {
 
-        if(building.getBlueprint().getBuildingGroup().equals(BuildingGroup.BANESTONE))
+        if(building.getBlueprint() != null && building.getBlueprint().getBuildingGroup() != null && building.getBlueprint().getBuildingGroup().equals(BuildingGroup.BANESTONE))
         {
             Guild playerNation = player.guild.getNation();
             City banedCity = ZoneManager.getCityAtLocation(building.loc);

src/engine/net/client/msg/VendorDialogMsg.java

@@ -128,7 +128,7 @@ public class VendorDialogMsg extends ClientNetMsg {
             if (contract == null)
                 vd = VendorDialog.getHostileVendorDialog();
             else if (npc.getBuilding() != null) {
-                if (BuildingManager.IsPlayerHostile(npc.getBuilding(), playerCharacter))
+                if (npc.getBuilding() != null && BuildingManager.IsPlayerHostile(npc.getBuilding(), playerCharacter))
                     vd = VendorDialog.getHostileVendorDialog();
                 else
                     vd = contract.getVendorDialog();