If you get the following error when attempting to use emerge:
# emerge [whatever]
These are the packages that I would merge, in order:
!!! ARCH is not set... Are you missing the /etc/make.profile symlink?
!!! Is the symlink correct? Is your portage tree complete?
Create a symlink to the latest profile with the following command:
ln -sf /usr/portage/profiles/default-linux/[arch]/[profile] /etc/make.profile
Where [arch] is your architecture, like x86, and [profile] is the latest profile, like 2006.1.