dpkg-reconfigure of xserver-xorg creates problem for users!

["Bruce M. Ward" <bmward@myrealbox.com>]

Hi all.

A recent install of the Etch release.
Root uses 'dpkg-reconfigure xserver-xorg' to change the video resolutions.
Root can start X no problems.
Existing user cannot login with gdm - returns to login box. User can login at text console but cannot start X (with startx). Gets 'caught signal 11'. User previously had no problems.
Root creates new user. New user has no problem.

It looks like a permissions problem, but I haven't been able to figure out where ...

Any ideas anyone?
Can anyone help?
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Bruce Ward          Christchurch, New Zealand