Well, that was a bit distressing. I was setting up my own Streams server. I somehow saw the .easyinstall folder, but not the install folder, so I went the scripted route. I nearly shit myself when I saw it install sendmail and uninstall postfix, taking my mail server out of service. Fortunately, uninstalling all the sendmail packages and reinstalling the postfix packages seems to have put things back to normal. Might I suggest some sort of "leave my mail server alone!" option?
While I'm at it, while it checked to see if mysql is installed and doesn't install mariadb if it is, it still tries to restart mariadb and not mysql, if that is what you have, multiple times.
I had to so some other things (create the database and cron job) manually that I expected to happen as part of the script but, in the end, things seem to be working.