Blightfall Worlds won't load!!!

[BlackYoshi1]

Hello everyone,

in the last days I started to play the Blightfall modpack. Everything went well but on one day it won't load my world anymore. When I choose it, it returns back to the main menu or to the world selection. I've given this modpack 3,5 gb RAM (my laptop has a total of 4 gb RAM) and also update ALL of my drivers but nothing helped. So could anyone tell me whats the problem? Or is the laptop just too bad for the pack? But I can't explain why it worked at the beginning. Generate a new world is also impossible. Same as choosing my world. 

I hope I'll get an answer because this modpack is AWESOME