.emacs.d permission denied

[RichT]

I sudo to root to set up a system, the set up command throws up a form
in my 'favorite' editor emacs and when I try to edit the form, after a
short time it starts beeping with
Creating directory: permission denied, /home/.../.emacs.d
I exit emacs and emacs produces a core file.

On the advice of this forum, I added
(setq auto-save-list-file-prefix nil)
to my .emacs file to no effect. The version of emacs is 21.3.1 on
Linux.

Does anyone have a suggestion? Around here everyone suggests that I
switch to a different editor.

        Richard