As Gnutella is a decenteralised network your client needs IP adresses that run a gnutella client in order to connect .
Normally Phex gets these adresses from the Hostcaches in your Auto Connect Hosts screen ( C ) and they are stored in your Host Catcher screen ( D )
But sometimes the default hostcaches don't work for several reasons (to busy, offline) ,so in order to get adresses you could try 3 possible solutions.
1 The first thing you could try is to add exta hostcaches in your Auto Connect Hosts screen ( C ).
At
gnutella uk they keep a list of working hostcaches.
Here are a few from their list you could add, Just copy (crtl-c) and paste (crtl-v) them to the box above your Auto Connect Hosts screen and click add.
gnet2.ath.cx:6346
gnutella-again.hostscache.com:6346
gnutella.hostscache.com:6346
gnotella.fileflash.com:6346
public.bearshare.net:6346
2 You could go to a "manual hostcache"
Gnufrog and copy a adress from their website into the connect box ( B ) and click connect.
If this fails just use another adress, once you are connected to a client you will get more adresses from that client.
3 You can download a large phex.hosts file from the Phex developers site at
Sourceforge
Just place this file into your phex directory where your phex.cfg is located and also raise the value mNetMaxHostToCatch in your phex.cfg file to 3000 or higher.
At
gnutella uk they also have a hosts file, they call it a gnutella.net file.
You can copy the adresses from that file and replace the adresses in your phex.hosts file (use a tekst editor like notepad to open your phex.hosts file)
If your Hostcatcher screen is nicely filled, but all connection attempts in the Connections screen ( A ) fail,
(this possible becouse the adresses you have don't always have a Gnutella client running)
you could refresh your Host Catcher screen by clicking reset so you get fresh adresses to connect to.
And make shure Auto Connect is enabled