Users should be aware that the code for this plugin appears to contain several PHP short open tags, i.e. <? instead of <?php, or <?= instead of <?php echo which may not be supported/enabled on all PHP installations – preventing the plugin from activating successfully in those environments where it is not possible to edit php.ini to enable this feature. For the sake of compatibility it is recommended that standard open tags should be used in preference to short open tags, i.e. <?php and <?php echo should be used, where applicable, throughout the code.
In addition, for completeness the plugin script should also end with a closing PHP tag, ?>
Once the appropriate changes are made, the plugin activates correctly, and all admin form variables are displayed/populated correctly.
Either that, or perhaps make it clear to users that the short_open_tags directive must be set to 1 in the users PHP installation.