With the firebug plugin you get the following error in the NAVT Config Page:
unterminated string literal $WP_Installation/wp-admin/js/common.js?ver=20081210 Line 377
In the js sources of the loaded js-files you'll find
Here everything following the first "navt_ns.add_log_text(" is skipped.
As a look in the server log reveals:
PHP Fatal error: Call to undefined function _e() in $PLUGINPATH/js/navtadmin.js.php on line 99
So when navtadmin.js.php is generated, no more php gets executed.
A workaround is to substitute the function calls to _e() in navtadmin.js.php with their respective strings.