[how to access forge]

how can i access forge mod loader for blightfall? ive added a few mods of my own and now it says i need to update forge mod loader to play, but i dont know how to get there

[Favorite first 5 day strategies]

1. Beta- by far, close to villages and water, also a huge mineshaft right under the base

2. iron is super easy to get i guess

3. build directly under and above the biodome, works great, you can build a farm and smeltery and storage

4. i like to get the kitchen quickly so i never really worry about it. chickens are a big thing for me cause of eggs

5. i love mithril armor, but i can work with invar

[loading world then kicks me back to title screen]

hi i really love this modpack, but ive been having trouble loading up my world. i open it up and it says loading world, then after a little while it kicks me back to the title screen with no explanation. ive opened the launcher console and i get this:

http://pastebin.com/0nUrLpPt

something ive noticed a lot in the report is Caused by: java.util.zip.ZipException: Not in GZIP format, anyone know what this means?

i really love this modpack and this world that i have ive gotten really far and i would hate to have to restart... again