I have the same camera. The canon zoombrowser and connect software -> total crap.
On mine, when I plug the camera in it used to pop up a window to select the application to talk to the camera, and in the window was a selection for zoombrowser. Now the box pops up and it has nothing in it.
I can still connect by doing it manually in zoombrowser.
There are some patches on the canon website. Didn't fix any of my problems but you can try them to see.