I need to determine whether it's specifically the motion blur thats the problem, or if its the render point that is the problem. So if someone with the problem could do the following that would be helpful .

1. Download >>this<< and extract the two files into your shaders directory (its a settings file and a red tint shader). Backup your settings file if needs be.
2. Start up halo and turn off motion blur using "pp_motion_blur_enabled 0" in the console.

If the screen is tinted red then it's a motion blur specific problem, if it stays black then its a render point problem.