I installed June's Patch Tuesday updates on my old Windows Vista box, rebooted, and restarted Shareaza, and now it cannot connect to DC++ hubs.
The only thing I changed since when DC++ was working was to install Windoze Updates and reboot.
Some one among the recent patches must have introduced a change in how networking works on Windoze, which was enough to somehow break Shareaza's DC++ leaf-to-hub protocol implementation, while not noticeably affecting anything else (except possibly BitTorrent; I haven't tried that since the update patches). Shareaza will presumably need a matching update to make its DC++ leaf-to-hub communications work correctly again in the presence of these Windoze patches.
Please look into this and release a Shareaza 2.7.9.1 with DC++ updated to work with recent Windoze Updates ASAP.