You can try to run the file gtk-gnutella directly from the src directory by typing
"./gtk-gnutella". Does that work? If not, what is the error message?

You should be able to run it from everywhere by typing "gtk-gnutella" after you did a "make install".

If you are using Fedora Core 2, you can alternatively go to the gtk-gnutella Sourceforge pages and fetch a ready rpm there.