Even when the file server section of the camera setup is correctly configured, there is one more piece of configuration to check first before full deployment.
If the camera has a built-in SD card reader, this will be automatically configured as the default first storage location for recording and if there is no SD card installed in the reader then initialisation of the external recorder fails.
To resolve this navigate to the following menu in the Admin interface for the camera:
General Configuration - Manage Hardware Expansion
By default this will have the SD card slot set as the default.
Just enter the IP address of the SnapServer to be used, save the settings and then the initialisation should work without any problems.