mit-scheme port fails with permission denied error

[jkh@…]

This does not happen for all ports (I am able to build scheme48 successfully, for example) but, in this example, mit-scheme fails with a rather bizarre error. Debug output is as follows:

jkh@wunga-> sudo port -d -v install mit-scheme
Password:
DEBUG: Changing to port directory: /Users/jkh/Src/macports/dports/lang/mit-scheme
DEBUG: OS darwin/10.4.0 (Mac OS X 10.6) arch i386
DEBUG: org.macports.load registered provides 'load', a pre-existing procedure. Target override will not be provided
DEBUG: org.macports.unload registered provides 'unload', a pre-existing procedure. Target override will not be provided
DEBUG: org.macports.distfiles registered provides 'distfiles', a pre-existing procedure. Target override will not be provided
DEBUG: universal_variant is false, so not adding the default universal variant
DEBUG: changing euid/egid - current euid: 0 - current egid: 0
DEBUG: egid changed to: 4294967294
DEBUG: euid changed to: 4294967294
DEBUG: could not read "/Users/jkh/Src/macports/dports/lang/mit-scheme/Portfile": permission denied
    while executing
"file mtime ${portpath}/Portfile"
    (procedure "open_statefile" line 46)
    invoked from within
"open_statefile"
    (procedure "check_variants" line 29)
    invoked from within
"check_variants activate"
    invoked from within
"$workername eval check_variants $target"
    (procedure "mportexec" line 7)
    invoked from within
"mportexec $workername $target"
Error: Unable to execute port: could not read "/Users/jkh/Src/macports/dports/lang/mit-scheme/Portfile": permission denied
To report a bug, see <http://guide.macports.org/#project.tickets>

[blb@…]

Same thing happened to me, I'm guessing you're on trunk instead of 1.9.1; seems to be because port is now using nobody instead of root in certain phases, and some path up to /Users/jkh/Src/macports/dports/lang/mit-scheme probably doesn't let nobody see things. I just did a mode 711 on one of my directories, and things worked out after.