... then you have the following possibilities:

1) Read the FAQ on

http://gtk-gnutella.sourceforge.net/index.php?page=faq

2) join the irc channel #gtk-gnutella on the server irc.freenode.net. A irc client for unix systems would be for example irssi, kvirc or xchat, on windows best choice is mIRC.
Ask there. You'll maybe have to wait when noone is alive, though, so be patient.

3) subscribe to the mailing list gtk-gnutella-users on sourceforge:

http://lists.sourceforge.net/lists/l...nutella-users/

And ask there...

Edit: If there is no response from a developer here, then I recommend registering and posting any bugs at https://sourceforge.net/p/gtk-gnutella/bugs/