No compatible nms block class found???

When ever I click on one of my minigame Signs I get this error in console.
"WARN No compatible nms block class found"
What does it mean?
Here is some of my sign code if this helps

Code:java

    @EventHandler
    public void onRightClick(PlayerInteractEvent e) {
        Action a = e.getAction();
        if (a.equals(Action.RIGHT_CLICK_BLOCK)) {
            if (b.equals(Material.SIGN) || b.equals(Material.SIGN_POST)
                    || b.equals(Material.WALL_SIGN)) {
                Location l = e.getClickedBlock().getLocation();
                Sign s = (Sign) l.getBlock().getState();
                if (s.getLine(1).equalsIgnoreCase(ChatColor.DARK_GREEN + "SHOP")) {
                    e.getPlayer().openInventory(shop);
                }
            }
        }
    }

 

ksbdude
Sounds like a WorldEdit warning, not an error. Shouldn't affect your plugin in any way.

 

Jup. This has nothing to do with your plugin. WorldEdit emits this warning upon first interaction with block after server start, if the version of WE is not build to work with the given version of NMS in this bukkit build.
It's because the newest stable version of WE is for CB 1.6.4 and therefore the paths to the NMS classes have changed in CB 1.7.2.
It only means that WE cannot use it's full potential.