This has worked for a few Vista users: Uninstall LW (start > all programs > LW > uninstall) & ZA. Now reinstall LW first. Finally, reinstall ZA. Installing LW before ZA seems to be the trick
Double check that the Windows firewall's off.
I can't find much info about your modem, but it doesn't seem to have a firewall.

In LW file > disconnect. Wait 10 minutes, then file > connect.

If you still can't connect, try deleting LW's preferences folder when LW's properly closed. You'll need to show hidden files & folders to be able to find the preferences folder. There are instructions here.
http://www.gnutellaforums.com/genera...der-vista.html
You'll know if you deleted that folder properly - when you start LW, you'll go through the setup wizard again.

If it's still not working, try the fix here (replacing gnutella.net file).
http://www.gnutellaforums.com/connec...t-fix-try.html
Those instructions are for XP, but you'll need to open LW's preferences folder called LimeWire...the same one that you deleted earlier. Then remove & replace the gnutella.net file there.