I had a problem with using Gnome Do to post to Twitter (not that I did it a whole heck of a lot). It said 'failed' everytime, but it would post anyways. Also, the popups at the top of the screen stopped working. Clearing out the Gnome Do plugins and restarting (logoff and back on again) fixed it.
To clear the plugins, do:
rm -rf ~/.local/share/gnome-do/plugins-*
You may be able to just restart Gnome Do, but I found it easier just to log off and back on again.