This is the XvT/XWA lobby client named after a captured IISD that was introduced after IGZ quit support for these games and before the community switched to Voobly for matchmaking. Nowadays, it's scarcely used, but the lobby server is still running. So if Voobly kind of breaks down, you can always switch to this.
Errant Venture needs to be run as administrator and in compatibility mode to function properly under Windows Vista or Windows 7 or later.
Furthermore, be aware that the Errant Venture client needs additional ports, 1001 and 2403-2404 both TCP+UDP, in order to be able to host.