Describe the crash

To Reproduce
Steps to reproduce the behavior:

Crash Log

Info (please complete the following information):

• Modpack Version:
  • 2.77.5
  • 3.0 BETA 5
  • Other:
• Server or Singleplayer:
  • Server
  • Singleplayer
• Version the world was created on:
  • 2.77.5
  • 3.0 BETA 5
  • Other:

Additional context

Also nothing.