I am having the same issue when trying to launch tekkit with the new launcher build 253
It would be nice if i Could still play it and just have that mod dissabled until the link gets updated.
here are my system specs if needed.
Operating System: Windows 7 Professional 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.130318-1533)
Processor: AMD Phenom II X6 1100T Processor (6 CPUs), ~3.3GHz
Memory: 16384MB RAM
Available OS Memory: 16382MB RAM
Page File: 13884MB used, 18877MB available
DirectX Version: DirectX 11
Lemme know if there is more info you need. Trying to switch over to a tekkit server from a bukkit mc and need to work out the kinks before i let people on. kind hard when i cant launch it due to a bad url link.