[Mediawiki-l] Trouble with upgrade from 1.12 to 1.13.5

[Andrew Thornton]

Hello,

I have been trying to update my wiki to 1.13.5, but I have been
getting the following error after updating the files and updating the
database (via update.php).

Fatal error: Call to a member function matchStartToEnd() on a
non-object in /webroot/includes/parser/Parser.php on line 2788

I appreciate any and all help.