Sorry I took so long to respond to your question.
I went to the link you suggested and it wasn't real clear so I suggest this link as well.
http://snopes.com/politics/religion/allah.aspPeople will believe want they want to believe. Many people will share an email like this because they really want to believe that Islam is evil and so is its followers. They also want to believe a Christian minister. Sadly, this man is a simple liar. Not only did he lie when he produced the email, but in at least two other questionings, he lied and even added to it. In the investigation of what happened, witnesses said nothing like this happened at all. The exchanges he said he had with an Imam didn't happen between anybody. It simply didn't happen. Of course, the other lie was the person that was there to show a film on Islam was an inmate, not an Imam. Simply an adherent.
Interestingly, the Islamic religion has over a billion members and many sects,same as we find in Christianity. There is no one that is a speaker for all of the sects in Islam as there is no one spokesperson for all the different sects in Christianity. No Imam could speak for all of Islam. In fact just between Shi'a and Sunni, the word Imam means two different things.
I always suggest if you receive an email that sounds odd, it probably is. If it claims to be filled with some sort of special knowledge, it probably isn't.
The Islamic religion is a beautiful religion that teaches peace and harmony. There are some fundamentalists that teach other than that, same as the Christian fundamentalists do. Care for more?