After installing the GDM port the following message is output to the system console when GDM is started:
Nov 4 09:05:41 mancuso gdmlogin: Wrong permissions on /usr/X11R6/etc/gdm/Sessions//.keep_me. Should be readable/executable for all.
chmod 755 /usr/X11R6/etc/gdm/Sessions/.keep_me
(Admittedly, I have no idea what this file actually does, but adding execute perms makes the message go away)
How-To-Repeat: Install GDM from ports and run it.
Over to maintainers.
Fixed. Thanks for reporting. FYI, this error was safe to ignore.