I downloaded all the latest tar.gz files for GTK+ : ATK, Pango, GLIB, and GTK+ I also downloaded and installed the pkg-config file that the installation guide said I needed. After installing it, I used emacs to edit the configure.in file to put these modifications into place as suggested by the guide:

CPPFLAGS="-I/opt/gtk/include"
LDFLAGS="-L/opt/gtk/lib"
PKG_CONFIG_PATH="/opt/gtk/lib/pkgconfig"
export CPPFLAGS LDFLAGS PKG_CONFIG_PATH

LD_LIBRARY_PATH="/opt/gtk/lib"
PATH="/opt/gtk/bin:$PATH"
export LD_LIBRARY_PATH PATH

Then I proceeded to install the files in the order GLIB, Pango, ATK and GTK+ as the guide said to do. I only managed to get as far as GLIB however. This is how I installed GLIB by the way:

tar xvzf glib-2.4.7.tar.gz
cd glib-2.4.7.tar.gz
./configure --prefix=/opt/gtk
make
su -c 'make install'

Then I tried installing Pango the same way. During the ./configure test, GLIB was not detected: "Could not run GLIB test program, checking why........The test program failed to compile or link"

Do you know why this is happening? I'm really new to linux, so could you please give tell me step-by-step what to do to fix this error? Thanks alot for your time!

I think your problem is a non recognized /opt/gtk folder as a binary and libraries filled folder.
try to do that
edit both to files /root/.bashrc and /home/yourusername/.bashrc
fill them with this

export PATH=\
/bin:\
/bin/:\
/sbin/:\
/usr/bin:\
/usr/local/bin:\
/usr/games:\
/usr/X11/bin:\
/opt/kde/bin:\
/opt/schilly/bin:\
/usr/X11R6/bin:\
/opt/gtk/bin:\
$PATH

IMPORTANT: Before do that see if that's the way your distro is organized... the only one that you need is the /opt/gtk/bin

Other thing edit /etc/ld.so.conf
and add /opt/gtk/lib
and do ldconfig

Ok, thx, I'll try it out and report if it works or not.

I havent fully tested the rest of the changes you told me to make, but apparently the shell doesnt recognize the Idconfig command.

bash: Idconfig: command not found

Any idea why?

it is ldconfig
LDCONFIG is an L
if you can't do ldconfig try /sbin/./ldconfig
or do ctrl+alt+f1 login as root and retry ldconfig

Ahhh...thank you very much. I'll try it out.