use of absolute url to plugin

I am wondering why the plugin uses an absolute url path:

$this->plugin_url=get_bloginfo("wpurl") . "/wp-content/plugins/$this->plugin_folder";

I have a problem in a wordpress installation where the plugins folder is relocated and this causes the plugin to not function correctly because of this. The plugins folder location can be redefined in wordpress configuration using WP_PLUGIN_DIR, WP_PLUGIN_URL, PLUGINDIR…

see
http://codex.wordpress.org/Determining_Plugin_and_Content_Directories

http://wordpress.org/plugins/hana-flv-player/

Thanks for looking into this.