I am using a theme called Responsive created by http://themeid.com
Couldn't find the code you mentioned.
I basically deleted all the previous themes as well, delete all the deactivated widgets and plugins... still AddThis just doesn't go away....
I like your widget, but it block out the whole left hand side content when user browses my site using iphone... and I received lots of people asking me to remove it. If I could choose not to display that long thing on mobile devices, I would consider to remove ShareThis and keep yours to make it simple, not a problem as it gets complicated having two widgets for the same purpose.
I am happy to give you my login credentials for my server and wordpress if you can fix it... I have tried everything. If you wish to check it out, please do send me an email to email@example.com