automount and setgid on dirs

[Armel de la Bourdonnaye]

we have an rs6000 320 with aix3.1-3002
we try to mount from a sun.
the command line is 
/usr/etc/automount -m -tl 300 -tw 300 /u -hosts -rw,intr
when the root user goes under an automounted directory 
with Drwxr-sr-x permissions everything is ok.
when it is not a superuper
if the directory is not mounted before, automounter refuses to do it
and if it is already mounted, automounter unmounts it.
In both cases we get something like
nfs_mount error 65: socket protocol family unsupported.

BTW we also have the SEGV error reported before.
Any idea of solution for both problems would be great.

We don't want static maps because we have 700 potential users
and a net of ~200 computers.
thanks for any help.