Thank you very
much. With this I've found the error, which
was in the default skin (a custom skin) - it worked fine
with 1.10 but I presume either the DB or a function has
changed its behaviour.
So it wasn't really mediawiki. That explains it. It was odd that it had
such a bug.
I don't think something which worked fine had a bug. Simply, MedaWiki
has changed its behaviour.
userNotLoggedInPage shows the useful page "You must login
to edit pages". However, this part has disappeared in 1.11,
and in fact now I think it's a bug. I'm studying if it can
be restored somehow, but this part has been rewritten and
I'm not sure what to do. I'll report it.
Treat it as you want. I find extremely useful not being told "You need
to login to edit" if i only want to view the page content.
I much prefer to encourage editing than viewing. Anyway, they are
not incompatible and MediaWiki could offer _both_. I've tried EditAtLogin
out, which does that, but unfortunately I've had some problems. I'll
continue investigating.
Javier