There isn't a lot to go on here I'm afraid, could you post the following:-
FTB Launcher version (if this isn't the newest update update and try again):
Minecraft Version:
Java version:
Detailed description of the issue / how can the issue be recreated:
Also slightly silly question, but forgive me, I notice you are getting a java.net socket exception, you do have an internet connection when running FTB? Also you might want to check your AV or Firewall isn't blocking the connection.