[Mediawiki-l] Pages loading blank

[Stuart, Ryan (CIV)]

Hello all,

I'm running MediaWiki v. 1.10.1, recently installed on a RHEL 5 machine
with MySQL 5.0.22 and PHP 5.1.6. I had no trouble installing the
MediaWiki software and a few extensions, and all seemed to be running
fine for a few days. But now the pages are loading blank, or if not
blank at first, a few clicks into the site will earn you a blank page.
Refreshing sometimes forces the page to load. No error message appears
on the page.

Error logs show this message:
PHP Fatal error:  Invalid opcode 134/1/1. in
/var/www/html/wiki/languages/messages/MessagesEn.php on line 847,
referer: [pagename]

The extensions I installed were the spam blacklist, the re-captcha
extension, and one that changes the layout of the Recent Changes pages.
As a test, I removed this code from the LocalSettings.php file, but the
blank page problem still occurs.

All help appreciated,

Ryan