Throwing this (http://pastebin.com/V3BFrwYB) in the console.

Steps to reproduce:
Place a PreciousStones block to create a protected area
Use /ps info to show the information of the area you just created
Remove the protection block
Use /ps info again, waiting for the "No fields found." message.
Get "Command not recognized" message + error in the console

Using latest version from BukkitDev (9.7.1, Dec. 26)

Try the latest version from Jenkins.

This should be the latest one...? http://repo.sacredlabyrinth.net:8080/job/PreciousStones/410/ Dec. 12th, the one from DevBukkit is from Dec. 26th.

Yep try that one, let me know if problem persists.

Yes it does. All three of the bugs.

Fixed. Try the new build.

#411 from Jenkins (/version preciousstones returns "9.7.1-SNAPSHOT"), still the same issue.

Using latest PreciousStones version from bukkitdev (9.7.1) is not throwing me this error when using the /ps info command. I only tried to use the command with permission node for /ps info set to true.

Using Spigot 1.8 Build 22

What server version are you using @UnusualToast ?

Spigot 1.8. Not sure what you mean with build #, though. Well, I don't remember setting up permissions, although I'm OP. Would that be it?

I mentioned what BuildTools - build # that worked with me, which is Build #22 (latest build at the time I'm writing this)
You can find the different builds from their jenkins: https://hub.spigotmc.org/jenkins/job/BuildTools/

You may have used the bash code to download the last successeful build (bash code can be found here http://www.spigotmc.org/threads/buildtools-updates-information.42865/)? In that case I have no idea how to tell what build you are using. I guess if I were you I would try getting the latest build today, or at least #22, because that version worked for me..

There is no guarantee this has to do with server versions though, I also tried as OP as well as having the preciousstones.admin.* permission set to true for me but it wouldn't trow the error.

Hmm.. Other than that I have no idea why it would work for me and not you :s Did you fetch the latest Vault version? If all fails, I thinkg I would try starting a clean new server and install only PreciousStones and Vault. If that doesn't throw the error, I would then try moving in parts of the actual server (that threw the error) and see when the error appears.

Good luck!

BuildTools # has nothing to do with Spigot version.

I didn't think of Vault either. Although I remember downloading its latest version, I will try that again later.

Aha, I completely misunderstood how the buildtools worked. I thought every new buildtools build included the newest spigot\craftbukkit\bukkit build >.<

Sorry about that, it was a stupid assumption o.o

If it helps, here is the spigot /version that worked for me: git-Spigot-b8f6402-a646500

EDIT: Never mind, I'm no longer having this issue..don't know what fixed it or what was causing it but It's fixed now.

I'm having the same issue as you @UnusualToast not to sure why.

I'm using a dev build of 1.7.10 Bukkit (Managed to grab it before the lawsuit :D)
And yes I've got the 9.7.1 snapshot, Vault is updated. ---> http://pastebin.com/hcHEL3V8

Also on a side note: City protection doesn't notify players that they are entering or leaving a protection field. No errors in console. (Could also be something on my end...)