Broken new page layout in MediaWiki 1.18.2
Ugh. Try refreshing your MediaWiki files except your LocalSettings.php; don't touch your database.
Nope, that didn’t do it either! :-(
…But why would that happen with “not [yet] existing”/empty pages only??
There must be some variable in the template that is undefined when a page doesn’t exist yet and that the header [template] depends on…
Any other ideas? I’ve upgraded to 1.19.0beta2 “just in case”, but still no joy… :-(
Anybody aware of specific incompatibilities between recent versions of MediaWiki and PHP 5.2.6 [and/or MySQL 5.0.95-log]? (Here I’ve got an instance of MediaWiki 1.6.8 and exactly the same versions of PHP and MySQL [on basically the same servers], and that problem doesn’t exist.)
Something is very broken with your webserver.
The response for those pages sends no HTTP headers at all.
Maybe a broken 404 handler. If you set $wgSend404Code to false in your LocalSettings.php - does that fix your issue?