Requesting help. While rendering, VVIS, Portal Flow gets stuck at 1..2.. It moves no further.

Tested on 3 PC's: Dual core, Quad core and a Six core and it gets stuck at the same point everytime. Suggestions?

I didnt have this issue before when rendering it in the CS:S Engine. The ONLY change from this and the Gmod map is that the CS:S spawns have been deleted and TF2 ones added. It is also being rendered in HDR, rather then LDR. Why the lighting change? SFM needs HDR lighting.

I also changed the skybox texture from the custom one to a Valve one, Nightfall.