Whelchey

Can someone explain why the hell the "New Tekkit Classic" pack keeps crashing??? I have 2 worlds that i got to a certain point on they both just keep crashing when I log in???

Login help? Launcher won't let me in even though I'm putting in my correct Username and Password?!

Im typing in my Username and Password correctly and is saying invalid credentials? I've changed passwords 3 times now and nothing is working.