You may want to try running the X server with Options "NoTrapSignals"
"Enable" in your
"ServerFlags" section and turn on DRI debugging to get more information.


The "can't find authenticator" simply means, IIRC, that the X server
making the request is no longer running. ;)  For instance, this can
happen if the X server makes an authentication request and then dies
because you have no core pointer device (assuming you don't configure
it that way on purpose, of course).

If you send DRI debug output from your message buffer and an Xorg log,
we could probably help more.

Regards,

--Blair