I had a problem with my server and had to re-import my database from backup and reinstall wordpress in a new folder. I then copied the plugin folders to the wp-content directory and activated / updated plugins. Strangely some plugins disappeared.
I deleted the wp-touch folder (amongst others) and reinstalled a fresh install of WPtouch Version 1.9.26.
The plugin works using an iPhone, but the option to add the wpTouch to the sidebar widget menu is completely missing.