There doesn't seem to be anything wrong with the language pack.
It does contain an XML file containing the following:
[code:1]<?xml version="1.0" encoding="iso-8859-1"?>
<cbinstall version="1.0" type="plugin" group="language">
<name>Danish</name>
<author>Danish Translation Project</author>
<creationDate>2007-06-03</creationDate>
<copyright>(C) 2005 - 2008 joomlapolis.com</copyright>
<license>
www.gnu.org/licenses/old-licenses/gpl-2.0.html GNU/GPL version 2
<authorEmail>beat@joomlapolis.com
<authorUrl>
www.joomlapolis.com
<version>1.2 RC 2</version>
<description>Dansk oversættelse af Community Builders hovedfunktioner</description>
<files>
<filename plugin="danish">danish.php</filename>
<filename>index.html</filename>
<filename>cbteamplugins_language.php</filename>
<filename>calendar-locals.js</filename>
<filename>images/index.html</filename>
<filename>images/nophoto.jpg</filename>
<filename>images/pendphoto.jpg</filename>
<filename>images/tnnophoto.jpg</filename>
<filename>images/tnpendphoto.jpg</filename>
</files>
<params>
</params>
<database>
</database>
</cbinstall>[/code:1]
Is there no way to install it manually?