I tried to fix it but it didnt work, mostly because i cant find my .techniclauncher/cache file, in fact i dont have a map from technic/tekkit, my computer can only find the launcher :/
So it still said 'Update Failed', any other suggestions would be nice...
i have the same problem, it automatically updates my technic launcher when i click login, on the end of the update a new small screen appears saying 'Update Failed' with a white i in front of it and it wont start the game...