So, if I am right, Technic team run all the Modpacks throught 1 server/service before running through the minecraft service. Or tough it makes pleanty of sense to do that it would be recomended that create a backup of the server to keep things runnign on, also I am still a bit uncertain if they realsied that on the update they last doen for tekkit classic it does not work. Infact it just crashes and tel you abotu an error with the modpack which is stated as a "nullpointer.expectation" I woudl highly reccomend fixing that as well "when they can" with respect. as it is the last upodate they did on classic. It is not clientside since I have foudn otu many people get it and its when they first run it after the install. meanig n the install is corrupted.