Tag suggest plugin doesn't seem to work in 7.9

After following the instructions on the forge documentation site, the tag suggest plugin doesn't seem to work. When opening a document with the plugin configured, the following message appears in the logs:

[INFO] [talledLocalContainer] 06.06.2014 13:31:49 ERROR http-bio-8080-exec-10 [PluginFactory.createPlugin:106] No plugin classname configured, please set plugin configuration parameter plugin.class
[INFO] [talledLocalContainer] Failed to instantiate plugin class 'null' for wicket id 'null' in plugin 'home.cluster.cms-static.plugin.navigator.cluster.cms-browser.plugin.navigator' (JcrPluginConfig:/hippo:configuration/hippo:frontend/cms/cms-browser/navigator)

To reproduce:

1. Create a 7.9 (1.09.00) archetype project

2. Follow the instructions on http://ecm-tagging.forge.onehippo.org/install.html

3. Open a text document, add some tags

4. Open another document, try to add tags from the tag suggest plugin

Expected: the tags in the other document appear as suggestions

Actual: no tags are suggested