Are you new to mining and Avalons? It kind of sounds like you are.
You should connect to your Avalon's and assign a static IP within your own network and make sure you assign the correct Gateway IP and DNS (usually it's 8.8.8.

otherwise they won't hash.
As soon as you log into your Avalon go to the CGminer Status link and you'll see the Firmware revision number.
A good firmware to get is from CK it ends in 0821
Yes, I am new to mining with Avalons. I did connect to the avalon and assign it a static IP and it did work for about 20 minutes. I unplugged it an literally moved it 2 feet and plugged it back in (same network cable and power cord) and it wouldn't reconnect and mine. I could still however get to its web based browser from another computer in the building so I know its connected to the internet.
Thanks for the info about the firmware, I still dont get WHICH file I'm supposed to download to update it. Its currently running 20130723.
To solve my networking problem, I used DHCP at the advice of an other forum member. Go to Network>Interfaces Where it says LAN, click edit. Under protocol change static IP to DHCP client. It will assign an IP address to the miner, you'll just have to discover what that is. For my wireless network, I was able to look at connected devices under my router's management page. I'm not sure how you'd find yours. But this worked like a charm for me. This new IP is what you'll use to connect to the configuration page for your miner.
EDIT: To flash firmware, download the firmware (for example,
this is Avalon's most recent), then in your miner's management page go to system>backup/flash firmware. Then browse for it and flash the image.