I just completed the update on my BD-P1400 and it worked fine. (I actually had to run it twice because my player was so out of date.) I checked my settings and noted that DHCP was set to off. That means that I manually input the IP settings. I have a cable modem and am running a standard Linksys network in my home. It seems that to get the IP address of the player, I went to the other computers on my network a looked at what their IP addresses were. Then I just increased the highest one by "1" and it worked. Not knowing how you are set up in your house, there may not be much else I can do for you.
You have two other options: You can leave DHCP to on and keeping trying to get it to assign an address automatically, or you can download the firmware from the Samsung website and burn it to a disk. You may want to get instructions off the Samsung website for burning the disk also.
Let me know how it goes. JMP