Have you manually changed any of the JBoss AS configuration files manually?
I suggest you try recreating a clean version of the installer again, using "ant clean.demo". This will clean the installer (other than the already downloaded files) so you can run ant install.demo again to end up with a new, clean version. If the problem persists, let me know and I'll take a look.
Script for starting server was written in a way that it couldnt run my ant. My ant path in PATH system variable was wrapped with "". I have removed " from PATH and everything runs ok now. I couldnt see it before bacouse ant was running with no problems from my console. I use Windows 7.