I have had similar problems and found a cure:
"A networking error has occurred: zero byte resource (-1014). Make sure you can connect to the Internet, then try again.
I was over helping a friend upgrade his mac, and he got that error. Others have gotten it too, but googling and finding the answer is strangely hard. I was able to solve it since I'd had the same problem in the past.
The fix is to set the network MTU to 1400. In a terminal, run sudo ifconfig en1 mtu 1400 you'll be asked for your password. Then do crontab -u root -e and in that file, type "@reboot ifconfig en1 mtu 1400". Save it and quit.
[Update 7 April 2005: I just added the important word "mtu" to the first both commands. Without that, this wouldn't work.
None of this makes any sense to me whatsoever, it might as well be in Chinese! can anyone translate into English