Just a guess -

fabs() is a python method of calculating the absolute value of a floating point number. As the COD2 engine has integrated Maya into its tool set using different programming languages - python being one of them - I would say the error itself wont be very helpful to any member of the public. It is a developer error.

Having said that, the real problem is the information in the Vec3Dot() (C++) method - that there is something wrong with your normals.