~/MacPorts/ports$ sudo port install socat
---> Computing dependencies for socat
could not read "/Users/mija/MacPorts/ports/sysutils/socat/Portfile": permission denied
I was having strange problems to use a locally edited portfile. Turns out the permissions were wrong in a directory in the path; each of the directories should have at least o+rx permissions, and strangely my $HOME had none of those (strange because other users in my computer had o+rx, admins or not).
Note that MacPorts lately (from 2.0?) has started to use the user nobody at some points of its workings, and root at others; in this case the user nobody was the one unable to reach the Portfile. A way to check what this user sees is "sudo -u nobody ls -leda@ /Users/mija/blabla".
A workaround is setting macportsuser in /opt/local/etc/macports/macports.conf to root, but that's not a good idea. MacPorts is doing the the sensible thing, de-escalating privileges when they are not needed; that way, if something went awry, the problems should be much smaller. Lion is doing a lot to be secure, let's keep it that way.
So fix those permissions, goddamit.