I am getting the exact same thing. I am using the 152ngt pack and it was working fine yesterday morning. I switched my PC off left for work. Got home switched the PC back on and it crashes on start up. IO have attached the log file.
Thanks for any help.
Edit: BTW I have deleted the 152ngt folder and redownloaded from the launcher and I still get the same problem. I can launch Vanilla 1.6, 1.5.2 and FTB ultimate. Its just this 1 pack I get this crash with.
Edit 2: Managed to fix it by deleting the whole folder where my FTB installs were. There was a folder called config with a denlib.cfg file in which I suspect was the cause of my problem. Strange that it just started happening randomly.