Issue:Articlecategory doesn't work in 1.6.8

Description:	articlecategory produces no output
Extension / Version:	DPL   /   1.6.8
Type / Status:	Bug   /   open

Problem

This example produces no output on MediaWiki 1.11.x and 1.12.0 on Windows 2003 Server.

<dpl>
namespace = Talk
articlecategory = My category
</dpl>

even if there are articles in "My category" that have talk pages. I would expect to see a bulleted list of all Talk pages whose main article is in "My category".

This problem exists in DPL 1.6.5 as well.

This is with PHP 5.2.5 and Apache 2.2.8 and mySQL 5.0.45-community-nt-log.