Are you sure they are for the GUI and not to be run in Terminal mode? Did you
download from the Ubuntu servers using Synaptic or their Ubuntu Download
Center? If a downloaded file ends in .deb, it'll be easier than those ending in
.tgz or .rpm...unless things have improved for newbies.

www.unixmen.com/.../937-things-to-do-after-installing-ubuntu-\
1004-lts-lucid-lynx

www.linuxforums.org/.../64958\
-how-install-software-linux.html

www.starryhope.com/.../ubuntu-restricted-extras-lets-ubuntu-play-e\
verything/