Hi, today I faced very same problem. I have UDK and several other 3D program installed inside an old machine and all runs smoothly, but Unreal 4 does not start at all. It fails silently. Log is about same reported here. Thanks for this post, I’ll try update my video card as well.
— Old Machine
AMD Athlon 64 Dual Core
4 GB
NVidia 6800GT
Windows 8 Pro
DirectX 11
Runs: UDK, Rhinoceros, Blender, Unity3d