Due to terrorism and attacks on Christians by Muslims in many parts of the world, it is safe to say that most Christian countries are fearful of Muslims. While most Christians will not be attacked by Muslims it is still a fear they carry due to media coverage and recent attacks.
The religion of Islam has a large number of literalist followers, who believe that Mohammed's Koran is the word of God to them. Verses such as Quran 4:74, which proclaims eternal life for those who kill and die for Allah, has led many Muslims to disregard their own lives and the lives of innocents in their quest to convert the world to Islam. In Christian countries, although the Old Testament speaks often of bloody war and violence, it is restricted contextually to an ancient theocracy in Israel, instead of a command to the devoted modern believer. Many people, especially in majority Christian countries, fear that Muslims are attempting to fulfill their own book's prophecy of an "Armageddon" end-times battle by provoking the world to attack them.
Part of human nature is to separate "us" from "them." For the entirety of human history, wars have been waged against those who were considered "sub-human." It continues to this day, although to a lesser extent because of the way that technology brings us together. The only thing that could unite the human race would be an even bigger "them" (aliens?) to focus on.
No, people are not fearful of Muslims in Christian countries; rather, people are fearful of terrorism. Terrorism is a real problem in the United States and Canada, but people are not fearful of Muslims. There are always one or two people with mental health defects that hurt others, but that isn't the majority of Christians.