it will let me in to 1.7.10 but it wont let me create a world . itwill crash

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...what I expected to happen was to let me make a world
3. ...what actually happened was it crashed when i creattted a new world and with mods to.