No Christian have grounds to be afraid of Satan. He has no power, nor do his followers, over Christians (namely the power of Christ in them). Satan is not equal with God, not even close, and therefore cannot come close to having the same influence, power, etc. As stated previously, there is a lot of ignorace going on with the general populace and Satanism. But it really is no different than any other religion that worships created beings rather than the self-sustaining Creator.
Admitedly, there is fear in the hearts of most people when Satan is mentioned, but wrongly so. I do not fear Satan in the usual sense of fear. I actually have a profound respect for him as a powerful adversary, and a great deal of pity for him knowing that his ways will find his end in destruction and eternal banishment. I do have fear; it is a part of my "emotional range." What I am saying here, as I think others are, is that our nature as humans is to fear the unkown and what is more powerful than us, but God gives us a much higher degree of power and strength than the fear that is settling in our hearts. I know for myself, when I get afraid (of anything; Satan, money trouble, future, etc), I pray, think of God, sing or read my Bible or something and He is faithful to pull my out of that fear.