SkinMonoBook::getTitle() fatal error after enabling Collection extension

[DG23]

I'm getting a fatal error when I restart Apache2 on Ubuntu 10.10 and
try to display my MediaWiki main page. The MW1.18-r100383.tar.gz
version of the Collection extension is installed and enabled. The
localhost install on mw server appears to be running okay. Browsing to
http://localhost:8899, for example, displays a "no command given" as
expected.

The Apache2 error.log displays, "PHP Fatal error: Call to undefined
method SkinMonoBook::getTitle() in /var/lib/mediawiki/extensions/
Collection/Collection.hooks.php on line 63" Presumably this was fixed
in 2009 so don't understand why I'm getting it.

Before I got this far, I had to change a line in Collection.php
because it reported a problem with $wgResourceModules in the Apache2
error log. I changed $wgResourceModules += array( to
$wgResourceModules = array( to make this error go away.

After I restart Apache2 service and browse to the main wiki page, also
on the same host, I get a blank white page and the SkinMonoBook error
is recorded in the error log.

Any clues at how to get past this?

[DG23]

I forgot mention the version of MediaWiki installed:

MediaWiki 1.15.5-1

PHP 5.3.3-1ubuntu9.6 (apache2handler)

MySQL 5.1.49-1ubuntu8.1

[Ralf Schmitt]

DG23 <dgir...@gmail.com> writes:

I would try to upgrade the mediawiki installation, you probably also
need to upgrade the collection extension in that case.

--
Cheers
Ralf