When right-clicking on a water tank (watertanksiding) from railcraft using a crystal capsule from witching gadgets, the server crashes, when trying to use the crystal capsule on the GUI of the tank, the server crashes and crashes again if the chunk where the tank is loads.

Its worth mentioning that this happened on a Kcauldron server.
Doesn't seem to happen on Single Player on regular forge server.

Crash log: http://vpaste.net/7xH65

Mods involved:
RC: 9.12.2.0
Witching Gadgets: 1.1.10

Thank you. I will let players now about this when we update modpack with new RC version to see if it will fix that.