After inspecting your plugin version 1.9.17 I found, that you provide localization of backend by utilizing gettext functions of WordPress. The Problem is, that you never load a textdomain, so even if I have a translation, it won't be loaded!
I placed for testing purpose the
load_plugin_textdomain('wptouch', false, 'wptouch'); at the plugin main file beginning and voila, it loads the translation out of plugins main folder.
Please update your plugin to be able to load translations!