Not saving all cells; Error: PlayerInteract, Scheduler

[Crafter213]

Using Jail v3.0.0 Beta (build 139) on
CraftBukkit version git-Spigot-899f5ee-1092acb (MC: 1.8) (Implementing API version 1.8-R0.1-SNAPSHOT)

When creating cells, the plugin semms to break after selecting a non-chest block.
This causes errors in the serverlog.
Ingame the Plugin only gives Messages like "Chest" or "no Chest" when trying to create more cells.

Afterwards only some cells get saved.
When using "/jail listcells ", the cells appear not in order ("cell_n7, cell_n3, cell_n9, cell_n8, cell_n17, ...")

Server.log:
While creating Cells:
http://pastebin.com/RTDmHbZX

Unloading the plugin:
http://pastebin.com/AqWmi9mD

[Crafter213]

Thanks :)