Hi,

In message "Re: [ ruby-Bugs-5351 ] Process.gid= fails on OS X"
    on Tue, 8 Aug 2006 17:56:07 +0900, <noreply / rubyforge.org> writes:

|It's that simple. Assign to Process.gid= as root and Ruby will send you an EPERM. setgid() from libc does not have this issue.

Strange.  It's just calling setgid() from libc.  Can you show us your
config.h if your interpreter is compiled by yourself?  In addition, can
you double check whether the process had root privilege?

							matz.