The XOOPS has been installed into /var/www/xoops

You should point this to the DocumentRoot of your web-server:
   # ln -s ../xoops /var/www/htdocs/xoops
   (make sure you use a relative symlink since Apache is chrooted)

Proceed to complete the installation by reading:
/var/www/xoops/docs/INSTALL.html
