oh, i know what's wrong. I had this issue when we updated the game last, so what was doen was i got the file from someone else. it's the WesterosBlocks.jar, so here's a link to download
https://ufile.io/w1xec and replace in your folder. I run on windows 8.1 so, this is how i did it
go into the %appdata% click on the computer's roaming that should appear. scroll and go into westetroscraft, instances westeroscraft-1.11.2, mods then delete the WesterosBlocks and paste the newly downloaded Westerosblocks jar in it's place. do not update the game when you do this or it will replace the jar with the corrupted file again.