+ $plugin_dir = str_replace('\\','/',WP_PLUGIN_DIR); // sanitize for Win32 installs
+ $plugin_dir = preg_replace('|/+|','/', $plugin_dir); // remove any duplicate slash
+ $file = preg_replace('|^' . preg_quote($plugin_dir, '|') . '/|','',$file); // get relative path from plugins dir