1) try telnetting to router4.limewire.com port 6346 - if you don't see a "gnutella ok", your access to gnutella has been blocked. It's entirely possible you never noticed before, because you usually don't need to connect to router4.limewire.com to connect to gnutella.
2) If 1) works, you might want to try connecting to router4.limewire.com manually.
3) If 1) doesn't work, try my gnutella.net file from
ftp://whitedragon.dyndns.org ( if the host isn't available send an email to
gregorio@gmx.li ).