Gnutella Forums - New to Linux... GTK help needed

Alright, I've been running Mandrake for a total of about half a week now so please bear with me if this is a bit of a newbie question.

I tried to install the GTK so I can run Gnutella, so first I set up GLIB (I'm using tarballs, btw) and there were no problems I couldn't work around myself. Now I'm trying to install ATK, it tells me it can't find GLIB. I get the following error:
"The test compiled, but did not run. This usually means that the runtime linker is not finding GLIB or finding the wrong version of glib. If it is not finding GLIB, you'll need to set your LD_LIBRARY_PATH variable environment variable, or edit ld.so.conf to point to the installed location. Also, make sure you have run ldconfig if that is required on your system.
If you have an older version installed, it is best to remove it. although you may also be able to get things working by modifying LD_LIBRARY_PATH"

So here's what I did:
-Went looking for ld.so.conf, which I found, but didn't really know how I'm supposed to edit it, becase it tells me it can't make a backup so the file remains unchanged.
-went looking for where I could change LD_LIBRARY_PATH but I have no clue a) where I'm looking for it or b) what path I need to change it to. I was originally under the assumption that if I installed the most recent version of GLIB to whichever default directory it wanted to, ATK and ultimately the GTK would recognize it there, wouldn't it? (For the record, the GTK _does_ recognize it there...).

Can anybody offer me any help? If you can't respond here, could you e-mail me at ebbomega@silliness.8m.com

Thanks for your help