yes you can but I see no reason why automatic won't work anymore.
We should check if your network interface i still working. To this you could try if you can connect to it using the the fvw-sl console that runs under windows.
This console you can download in the download section. The u-boot terminal in this program also should work for the nwsp1.
The u-boot console will interrupt boot and displays a u-boot command prompt. If this works then the network interface is ok and we there must be an error in the nas database or other part of the firmware.
If I remember well the error you have could also be cause by a corrupt nas database. I would try first to do the check with the fvdw-sl console to test the network interface.