MC heli not working

MC heli is causing an error when trying to load the modpack and i have no idea why. 
![image](https://user-images.githubusercontent.com/42423708/44179462-0d7b8380-a0c5-11e8-9849-76a1d6083086.png)
if there is a way to fix this i would like to know so i can play the modpack