You got it!  Because I recently upgraded from NetBSD 1.5.3 to 1.6 I had
a "bad" .Xauthority file.  I removed the old .Xauthority and added the
following code to my .xinitrc:

if ! [ -f ${HOME}/.Xauthority ]; then
   xauth -f ${HOME}/.Xauthority -v generate :0.0 . trusted
fi

> 
> "David Forrai" <david.forrai@gemair.com> wrote:
> 
> > AUDIT: <date and time> <X server PID> X: client 1 rejected from local
> > host Xlib: connection to ":0.0" refused by server
> > Xlib: No protocol specified
> 
> Do you have valid $HOME/.Xauthority? "xauth list" should show at least
> one cookie:
> 
> $ xauth list
> <HOSTNAME>/unix:0  MIT-MAGIC-COOKIE-1 <HEX DATA>
> 
> Christian