Mills Thatcher

PLEASE HELP! Im starting to get very mad because I cant play with my friends.

I can play tekkit classic fine without any problems, but when I try to get on my server the entire game crashes! It will just sit there for a second then a blank screen will appear. Ive tried re-downloading the launcher multiple times but nothing is working.

I can play Tekkit fine offline but whenever I try to get on my server the launcher crashes and I don't know how to fix it. It will just sit there for a sec and then a white screen will appear and thats it. Does anyone know how to fix this??