not working correctly for our server

[QuenyaMyth]

I was using this plugin on a spigot 1.7.9 build now 1.7.10. I also tried using the plugin with CB 1.7.9 and 1.7.10 with no luck. I use the plugin with MySQL, The plugin loads fine and lets users create shops and can add some kinds of items but not others such commands as browse and find dont work havent gone through them all here is a couple stack traces:
http://pastebin.com/kzCmGRmQ
http://pastebin.com/3RR0gTY5
http://pastebin.com/82Dn0c1X

[JeremyFail]

I have been having this same problem on my server as well. I'm running CB 1.7.9-R0.2. I also tried it on 1.7.10 and it didn't seem to work then either. It generates the same errors as well.

[aeheathc]

Which items are/aren't addable?
The error you posted suggests the Bukkit method "getMaxDurability" is now sometimes returning null, which it has never done before. If I can identify a pattern then I may be able to handle the null properly.

So i was testing the shops; what items can be added and what cant. I find that any item that isnt a block (from torches to ingots to diamonds to flowers to reeds to ect.)will bring up the error. I also have found that all storage blocks exept the coal storage block cant be added in to the shops. The blocks i know of that work are any type of wood, storage blocks (exept coal) endstone, dirt, cobblestone, stone, sand and grass blocks work. I think sapplings may work but im not sure i cant remember.
(i tested this on QuenyaMyths server)

[JeremyFail]

Well I have the same problem. I tried adding stone, that worked fine. Tried to add seeds or sugar cane or torches, it didn't. But I had problems running a lot of the other commands too. And if I ran the command /shop browse or /shop set it would give me the "An error has occurred" in chat, and it generated an error.

Though this could be a problem on my side, I'm not entirely sure. I'm not a programmer, not yet anyway...

I'll paste several links here with different errors. In the 4th link you'll see that adding stone worked fine compared to the seeds.
http://pastebin.com/0M3cJ0Ud
http://pastebin.com/annDviTz
http://pastebin.com/KYQPXws0
http://pastebin.com/hChe0Erh
http://pastebin.com/FZhgLRHh
http://pastebin.com/7MjVwMVH
http://pastebin.com/ZmVQTP86