MobRider WorldBorder

22:19:04 [WARNING] Task of 'WorldBorder' generated an exception
java.lang.ClassCastException: org.bukkit.craftbukkit.entity.CraftSheep cannot be cast to org.bukkit.entity.Vehicle
        at com.wimbli.WorldBorder.BorderCheckTask.checkPlayer(BorderCheckTask.java:68)
        at com.wimbli.WorldBorder.BorderCheckTask.run(BorderCheckTask.java:29)
        at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:126)
        at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:512)
        at net.minecraft.server.DedicatedServer.q(DedicatedServer.java:212)
        at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:476)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:408)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)