on Fri, Nov 22, 2002 at 12:10:35PM -0700, Eric Fox wrote:
>   bsd005(foxe): su -
>   Password:
>   su: setting user context: Invalid argument
>   bsd005(foxe):

setusercontext(), the function that raises this error, logs more
verbose information via syslog. you may want to log in as root and
have a look at /var/log/authlog for more details.

if this fails to reveal anything, whilst as root (in single user mode,
i suppose) you may want to try running ktrace on su, and seeing what
fails last by examining the output with kdump.