Error Message When Trying To Execute A Command

when i try to execute the command with all players (@a) it works well, once i try to execute it in the closest player it makes that error : https://pastebin.com/F4s8tRDE

[14:13:53] [Server thread/ERROR] [Sponge]: Error occurred while executing command 'giverandom give Megumii' for source noppes.npcs.NoppesUtilServer$1@7ca6abd3: null java.lang.NullPointerException: null at giverandom.giverandom.commands.GiveRandomCommand.processReward(GiveRandomCommand.java:111) ~[GiveRandomCommand.class:?] at giverandom.giverandom.commands.GiveRandomCommand.execute(GiveRandomCommand.java:72) ~[GiveRandomCommand.class:?] at org.spongepowered.api.command.args.ChildCommandElementExecutor.execute(ChildCommandElementExecutor.java:255) ~[ChildCommandElementExecutor.class:1.12.2-2838-7.4.7] at org.spongepowered.api.command.spec.CommandSpec.process(CommandSpec.java:388) ~[CommandSpec.class:1.12.2-2838-7.4.7] at org.spongepowered.common.command.SpongeCommandDispatcher.process(SpongeCommandDispatcher.java:355) ~[SpongeCommandDispatcher.class:1.12.2-2838-7.4.7] at org.spongepowered.common.command.SpongeCommandManager.process(SpongeCommandManager.java:360) ~[SpongeCommandManager.class:1.12.2-2838-7.4.7] at net.minecraft.command.ServerCommandManager.func_71556_a(SourceFile:665) ~[dh.class:?] at noppes.npcs.NoppesUtilServer.runCommand(NoppesUtilServer.java:213) ~[NoppesUtilServer.class:?] at noppes.npcs.NoppesUtilServer.runCommand(NoppesUtilServer.java:146) ~[NoppesUtilServer.class:?] at noppes.npcs.NoppesUtilPlayer.dialogSelected(NoppesUtilPlayer.java:303) ~[NoppesUtilPlayer.class:?] at noppes.npcs.PacketHandlerPlayer.player(PacketHandlerPlayer.java:158) ~[PacketHandlerPlayer.class:?] at noppes.npcs.PacketHandlerPlayer.lambda$onServerPacket$0(PacketHandlerPlayer.java:44) ~[PacketHandlerPlayer.class:?] at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_311] at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_311] at net.minecraft.util.Util.func_181617_a(SourceFile:46) [h.class:?] at org.spongepowered.common.SpongeImplHooks.onUtilRunTask(SpongeImplHooks.java:331) [SpongeImplHooks.class:1.12.2-2838-7.4.7] at net.minecraft.server.MinecraftServer.redirect$zjh000$onRun(MinecraftServer.java:4682) [MinecraftServer.class:?] at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:723) [MinecraftServer.class:?] at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397) [nz.class:?] at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?] at java.lang.Thread.run(Unknown Source) [?:1.8.0_311]

any idea what can i do ?