You do not use DVBLink Connect! Server, right? Just rename nb_server.dll from dvblink\sinks\nb_server into nb_server.dll.old and service will start up again.
I also advise that you ugrade to 4.1 any time soon. It has this and a number of other important bug fixes.
Server: Synology DS212j, TBS5980CI (Dutch CanalDigitaal), TeVii s660 unicable Astra 28.2E, DVBLink TVSource 4.6.0, all DVBLink EPG Loaders
Clients: AsRock ION 330 Win7 MediaCenter, Samsung DLNA TV, IPad, Samsung Galaxy S, Nexus 7