At the moment, I am in the middle of the same process you described, one thing I found, and am hoping works, is that not all of the necessary gnome packages are in the gnome directory. You also have to go to the "l" directory to get a few library packages (gtk+2-2.4.4-i486-1.tgz, glib-1.2.10-i386-10.tgz, and gdk-pixbuf-0.22.0-i486-1.tgz)
As I said, I'm in the middle of this process now, and on dialup. The gtk+2 package weighs in at about 5 megs, so it might be a little while before I can tell you if this works out or not.
If you've already tried this, I apologize for being redundant.
--- update ---
Also update pango and glib2 from the library package directory ("l"), that worked for me.
Everything is back in order...now I just need to blow away my configuration stuff for gnome because some of the old panel stuff is no longer supported apparently
Hope this helps.