What is exactly a root password and why should I have one? Why is not enough to have an administrative password? This root password I need is the ordinary Unix root password I use on my Linux? Should I put it in global.cnf?

This password is used to login to the Alkaline's management section. It must be specified in the global.cnf file. Please refer to http://www.vestris.com/docs/alkaline/cnf-accessstruct.html for more information.