[20:48:31] [Server thread/INFO] [Minecraft/]: Server permissions file permissions.yml is empty, ignoring it
[20:48:54] [Server thread/WARN] [Minecraft/]: Unexpected exception while parsing console command "op Mew_rebirth"
java.lang.IllegalArgumentException: Sender cannot be null
	at org.apache.commons.lang.Validate.notNull(Validate.java:192) ~[Validate.class:2.6]
	at org.bukkit.craftbukkit.v1_7_R4.CraftServer.dispatchCommand(CraftServer.java:714) ~[CraftServer.class:?]
	at org.bukkit.craftbukkit.v1_7_R4.CraftServer.dispatchServerCommand(CraftServer.java:697) [CraftServer.class:?]
	at net.minecraft.server.MinecraftServer$6.evaluate(MinecraftServer.java:1785) [lm.class:?]
	at net.minecraft.server.MinecraftServer$6.evaluate(MinecraftServer.java:1775) [lm.class:?]
	at org.bukkit.craftbukkit.v1_7_R4.util.Waitable.run(Waitable.java:24) [Waitable.class:?]
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:869) [MinecraftServer.class:?]
	at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:423) [lt.class:?]
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:798) [MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:658) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_161]