[18:52:05] [Server thread/WARN]: Couldn't process command: 'help'
java.lang.NullPointerException
at gaia.util.GaiaICommand.func_184882_a(GaiaICommand.java:399) ~[GaiaICommand.class:?]
at com.feed_the_beast.ftbu.ranks.Ranks.checkCommandPermission(Ranks.java:239) ~[Ranks.class:?]
at com.feed_the_beast.ftbu.ranks.CmdOverride.func_184882_a(CmdOverride.java:65) ~[CmdOverride.class:?]
at net.minecraft.command.CommandHandler.func_71557_a(CommandHandler.java:198) ~[k.class:?]
at com.matthewprenger.helpfixer.HelpFixer$1.func_184900_a(HelpFixer.java:40) ~[HelpFixer$1.class:1.4.15]
at net.minecraft.command.CommandHelp.func_184881_a(SourceFile:73) ~[al.class:?]
at com.feed_the_beast.ftbu.ranks.CmdOverride.func_184881_a(CmdOverride.java:59) ~[CmdOverride.class:?]
at net.minecraft.command.CommandHandler.func_175786_a(CommandHandler.java:104) [k.class:?]
at net.minecraft.command.CommandHandler.func_71556_a(CommandHandler.java:83) [k.class:?]
at net.minecraft.server.dedicated.DedicatedServer.func_71333_ah(DedicatedServer.java:423) [ld.class:?]
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:388) [ld.class:?]
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:613) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:471) [MinecraftServer.class:?]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_131]

I think there's a help command not implemented correctly. I tried using the helpfixer mod to fix it but it didn't work.

I believe this is fixed in the 1.5.5 version of this mod.

Credit goes to combusterf for the fix.