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 DS214Play, DVBSky S960CI Astra 28/23/19 (CanalDigitaal subscription), TeVii s660 Amos 4/Sirius, DVBLink TVSource and TV Adviser (GB) 5.1.0
Clients: AsRock ION 330 Win7 with XBMC 13.2, RPi with XBMC 13.2, Samsung Galaxy S3, Nexus 7