hi, actually i don't have any other missing widget, i can try again to disinstall all the plugin, remove all the files from ftp and then reinstall it again, if you think this could be a solution.
It has all started when i updated the plugin and got that error mentioned by ejrodgers, i've deactivated the widget but not the whole plugin, then when i've uploaded the plugin again, i found that situation in the widget section; i haven't touched anything more as far as i can remember..