On 15/09/2010 07:47, Will Robertson wrote:
> Is there any chance that this the same problem that's been reported recently here:
>
> <http://github.com/wspr/fontspec/issues#issue/69>
>
> ? (I haven't had time to look, yet.)
> Is there conceivably a bug in etex.sty?
>
> -- Will

The issue is different, but occurs because \fontspec_save_family:nT 
does \global\newcount which then chokes if the extended mechanism is 
being invoked. That is at least something to know about etex's version 
of \newcount: perhaps it can be worked around, but I've not yet tried.
-- 
Joseph Wright