Firefox a Thunderebird v debian 5.0

Neviem mi prosim niekto povedat ako nainstalujem Firefox 3.5 a thunderbird 2 di debianu lenny (prosim neodpovedajte ze ved tam iceweasel a icedove)

vzdy ked si napr stiahnem firefox pre linux tak :

/home/laufem/.firefox 3.5/firefox/firefox-bin: error while loading shared libraries: libgtk-x11-2.0.so.0: cannot open shared object file: No such file or directory

a neviem ako tuto kniznicu doinstalovat