Has the work, A Course in Miracles, been edited, changed, and corrupted to alter the meaning of some of the teachings as was done to the Holy Bible?

It, as well, has been heavily edited and that is why it is missing key pieces of knowledge that would help focus things on the opposition to the divine that is quite real and ever-present. Without a divine partnership you will fail, because as a physical being you are outmatched by more powerful physical beings—it is that simple. Being spiritual is the first step but then needs to be followed by engaging actively in partnership with the source of spirituality to assist you in dealing with the problem of evil in ways that have a chance to be effective.