For security reasons, some display managers forbids root login.
KDM by default seems to allow it, while GDM disallows it.
You may edit the GDM configuration file manually (I don't know the exact path on FreeBSD, should be somewhere inside /etc) and there is an option there which allows you to change to enable root login.
Unix is from the ground up a multi-user OS. Therefore, there is a clear distinction of user and administrator (you have a similar notion in Windows NT+ world, but different implementation). GDM configuration is a system-wide affair. It is not anything you do to your own user account, and therefore you need root privilege to use the GDM configurator, which writes to its configuration file that I mentioned.
I think you can install gnomeicu by
pkg_add -r gnomeicu2
(just type this at the command prompt)
This uses the "packages" app installation method to do all downloading and installing work for you automatically. This is most probably what you want. You can alternaticely use the "ports" system to automatically fetch, compile and install software packages. For more detail on software installation on FreeBSd, see
http://www.freebsd.org/doc/en_US.ISO...ook/ports.html
If you download tarballs manually, usually you do it on Unix systems by three consecutive commands as root
./configure
make
make install
(that's also what the gnomeicu docs said)
which set up compilation parameters, compile, and install respectively. However, because of the way FreeBSD organizes files it may be possible that extra options needed for ./configure, and so you would get a better chance to succeed using packages or ports instead. If errors occurred in any of these commands, then you are out of luck if you can't manage to figure out the options needed. If successful, this app will then be installed systemwide so every user on the system would have access to the app.
Right click on the desktop and you ought to be able to create a shortcut to mozilla. Try it yourself.