This effect is caused by the skin shader. (Been there... done this before...)

Go to the material room and pick some body part... say the chest. Click the advanced tab. Look about 6 lines down for "Ambient color." Dollar to donuts it's some shade of red. A lot of the people creating mats these days do this to help with skin tone, but when the light levels are really low, this screws the pooch, letting the character "glow."

Sadly, the only answer is to go through each and every major body area and set the "Ambient value" to zero. Set "Skin Head" through "Skin Leg", then hit "Toenails," "Fingernails," and "Skin face." All should have a zero value for "Ambient Value."

Your model will now render correctly in low lights. Remember to save a separate copy for your normal light renders, as the red tone DOES help in good light.