Im afraid I'm having the same problem.
How the problem started
I noticed that my Tekkit frame rate whilst playing was around 4fps, where as in the past it was usually 55-60 fps. I went on to my normal minecraft, and achieved the 55-60 fps mark easily, without flaw. There was also the fact that for some reason I couldn't set Tekkit's max memory above 1.5Gb. So i assumed something was wrong with Tekkit or the technic pack, and began re-installing.
I downloaded the .exe version of the technic launcher, enterred my details, changed the options to 4Gb RAM, at which point I was thinking "Yay its fixed." I then chose Tekkit and began the reinstallation. However, the launcher did not complete the download, and showed a "Download Failed" message. I tried again, and got similar results, but at a different percentage. Multiple attempts yielded different results.
At one point I managed to get to 96% of the minecraft.jar, and then the loading bar was flickering between the other parts of the download and the 96% for minecraft.jar. It reached mAtmos before saying Download Failed again. When i tried after this, I got in, but Minecraft came up with a crash report before I even reached the Mojang splash screen. Here is the crash report:
I have tried doing it after deleting the tekkit folder in the .techniclauncher folder, to no avail. I have also attempted the same with the Yogbox to check if the problem was just with Tekkit. It yielded similar results.
I dont believe its an anti-virus problem, because I had my anti-virus program the first time I installed the technic launcher.
Specifications:
Technic Launcher: 1.0.1.3
Operating System: Windows 7 Home premium 64bit
Java Version: JRE 7 64bit
Antivirus: AVG 2012 Free
EDIT: I also tried with the .jar file for technic launcher, and came with the same results.
EDIT 2: Just tried with normal vanilla minecraft too, and it resulted in the Download Failed message.
EDIT 3: I also noticed that the animation showing all the creators doesn't go past the Atom bomb guy, and that sometimes the background fails to load.