When trying to add an IP camera, there are not enough camera selectors available under "Channel Assignment" for viewing live video.
Pelco Video Management
The 4700/4800/4700HD/4800HD DVRs do not have more live display views than the number of analog inputs.
A) Reassign which cameras you want in the "Channel Assignment" setup option to your desired layout. If all the channel assignments are occupied however you will have to remove one camera completely from the live view to add the IP camera.
B) The DX Series Client will be able to view all the cameras on the DVR regardless of the configuration of the Live View at the DVR.