The driver for your network adapter is not being loaded.
You need to go in to your live system find out which adapter you have an what driver is being loaded for it, you can do that looking at the output of
lspci -nnk | grep -i net -A2 in a terminal, for me I get the following:
03:00.0 Ethernet controller : Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller [10ec:8168] (rev 02)
Subsystem: Micro-Star International Co., Ltd. Device [1462:7550]
Kernel driver in use: r8169
then in your minimal CD installation you need to go to another TTY and manually load the necessary driver module for your listed adapter.
I am sure you probably know this, but here are some questions for future reverence:
And here is more information on how to list and load driver modules using a TTY: