Yeah, what we have here is a Vista glitch as Vista and MXO don't work so well together, as can be seen here http://forums.station.sony.com/mxo/..._id=36300009145
Good news is, the vista problems are currently being worked on so with any luck this kinda stuff will soon be a thing of the past. But in the meantime there is a work around for the shadows on faces.
Create a notepad document and save it as useropts.cfg inside your Matrix Online folder in your computer, then copy and paste these lines into the useropts file and save it:
modellighting_enable = 0
modellighting_ambadd_r = 0.33
modellighting_ambadd_g = 0.33
modellighting_ambadd_b = 0.33
PlayerFX_LightPool_Bright_Scale = 0
Then restart your game and hopefully no more shadowy faces
Hope that helps.