I can't connect using NetDVR client. I receive the "unknown devtype" message. Through IE browser I can connect using Netdvr plugin. I use Windows XP SP3.
On the official website where the software is hosted (Google Code) there is a manual for a DVR which explains how to connect to various sources. I recommend downloading that user guide to learn how to configure your device.
Secondly, make sure that your devices can be accessed without the NVR. Paste the IP of the cameras into IE or any other favorite browser and configure them using the ports, username, password etc., then note down those settings and add them into the NVR. I've tried with my local NVR and it works normally without issues and did exactly like I said above.