libgtk-x11-2.0.so

i want to install firefox in my lab pc running dunno-waht-version-of-redhat and having kernel 2.4.2 the installer has necessary permissions ,it's -rwxr-xr-x but i thows up error msgs that it can't find libgtk-x11-2.0.so how to make it install? and if I can't get it to install,is ther any...