Hello. When me or some player accept a quest, in the console it appears an error and it doesn't tell the player the information of the quest.

The console error:
[13:31:08] [Server thread/WARN]: java.lang.NullPointerException [13:31:08] [Server thread/WARN]: at me.blackvein.quests.Quester.getObjectives(Quester.java:461) [13:31:08] [Server thread/WARN]: at me.blackvein.quests.Quester.getObjectivesReal(Quester.java:417) [13:31:08] [Server thread/WARN]: at me.blackvein.quests.Quester.updateJournal(Quester.java:290) [13:31:08] [Server thread/WARN]: at me.blackvein.quests.Quester$1.put(Quester.java:52) [13:31:08] [Server thread/WARN]: at me.blackvein.quests.Quester$1.put(Quester.java:45) [13:31:08] [Server thread/WARN]: at me.blackvein.quests.Quester.takeQuest(Quester.java:346) [13:31:08] [Server thread/WARN]: at me.blackvein.quests.Quests$QuestPrompt.acceptInput(Quests.java:497) [13:31:08] [Server thread/WARN]: at org.bukkit.conversations.Conversation.acceptInput(Conversation.java:229) [13:31:08] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_10_R1.conversations.ConversationTracker.acceptConversationInput(ConversationTracker.java:58) [13:31:08] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_10_R1.entity.CraftPlayer.acceptConversationInput(CraftPlayer.java:1044) [13:31:08] [Server thread/WARN]: at net.minecraft.server.v1_10_R1.PlayerConnection$5.evaluate(PlayerConnection.java:1207) [13:31:08] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_10_R1.util.Waitable.run(Waitable.java:24) [13:31:08] [Server thread/WARN]: at net.minecraft.server.v1_10_R1.MinecraftServer.D(MinecraftServer.java:742) [13:31:08] [Server thread/WARN]: at net.minecraft.server.v1_10_R1.DedicatedServer.D(DedicatedServer.java:400) [13:31:08] [Server thread/WARN]: at net.minecraft.server.v1_10_R1.MinecraftServer.C(MinecraftServer.java:668) [13:31:08] [Server thread/WARN]: at net.minecraft.server.v1_10_R1.MinecraftServer.run(MinecraftServer.java:567) [13:31:08] [Server thread/WARN]: at java.lang.Thread.run(Unknown Source)