Sponge crash

Hi everyone i started a server but i recieve this crash error every time i open it, i will post the code of the crash so you can see it and help me. I posted also the error in the ic2 forum and they said is an error from sponge.

sponge version: 1.11.2-2393-6.1.0-BETA-2605

ic2.core.block.machine.tileentity.TileEntityPump

Block location: World: (-329,69,249)

i now but why this happens???