the problem is that you are passing the page name as a part of the URL variable.
your links should pass the zulu URL variable to the zulu.php page, for example:
zulu.php?zulu=about
or:
zulu.php?zulu=services
then in the settings for the plugin, use:
page title / plug-in source | Variable Value[new value]
-plugins/about.php [about]
-plugins/services.php [services]