That's odd. I know some commercial games have had their blood-red gore turned green for release in certain countries, so all I can think is that it's a software localization thing - as far as I know everybody else gets a red blood splatter.
The graphic for the blood hit can be found here:
Files\gamecore\decals\blood
It should be red - if yours is green then I'd suggest opening it in a graphics program and altering the hue.
The weird thing is I'm almost certain that a few months ago there was someone wondering how you could make the red blood turn green for alien enemies - it's a funny old world
Cheers
- Graham