I saw your plugin and wanted to try it out ... I'm using MAMP Pro with PHP 5.3.x on a Mac and the plugin installs ok.
When I choose any option from the Debug This I get an error like this ....
Fatal error: Cannot use object of type WP_Error as array in /Volumes/Proust/Sites/dev/wp-content/plugins/debug-this/debug-this.php on line 183
just wondering if its something I've done?