No matter what I try, I cannot give players permission to place fields. I removed all other plugins and they weren't the cause. I have the latest craftbukkit and latest version of this plugin. Please help!

When I put any sort of permission in the permissions.yml file, I get this error in the console

[16:42:49 ERROR]: Permission in permissions.yml was already defined
java.lang.IllegalArgumentException: The permission preciousstones.benefit.fields
is already defined!
at org.bukkit.plugin.SimplePluginManager.addPermission(SimplePluginManag
er.java:578) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.loadCustomPermissions(Craf
tServer.java:687) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.enablePlugins(CraftServer.
java:288) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.reload(CraftServer.java:63
2) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at org.bukkit.Bukkit.reload(Bukkit.java:279) [craftbukkit.jar:git-Bukkit
-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:
23) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:19
9) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.dispatchCommand(CraftServe
r.java:544) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.dispatchServerCommand(Craf
tServer.java:531) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at net.minecraft.server.v1_7_R1.DedicatedServer.aw(DedicatedServer.java:
286) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:2
51) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:5
45) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java
:457) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:6
17) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]