Kodicom DigiNet Center(v4.100)

Hi. Ive setup the Dvrnet v4.1 site software on pc using two 8 port Diginet pci cards. All appears ok and the site software runs well. The machine is stable and no crashes or gliches to report. I have proceeded to install the client software of the same version on another pc on my LAN. The software connects to the site software and assumes all functionality except for the fact that I get black screens where the video should be displayed. The time stamps tick away as if the footage is playing but no picture. When i go to the search option from the client program the same happens. I can skip to an earlier time where there is footage but when i play it the screens are black.
Can anybody help out here?