path error

Yes, to your question of default_controller = Welcome. Let me ask the same question from a different perspective. In any configuration the "/" is used to parse folder information. Until faced with this situation, I have never thought what happens when you parse a file "index.php" and supply a "/" as the first argument. I don't know if there is a setting in my configuration that defines how to resolve it. When i execute http://www.xyz/common/index.php everything works as expected. It's when I add the "/" at the end that my site does not know I'm supplying a program and not a folder.