I had the same problem with my ELPH 330 HS and called customer service yesterday. Here's what needed to happen to fix it:
1) In the "Canon" folder under "Program Files" that is created when you install the software, there is a subfolder called "WirelessCameraConnectionSetting". Within that folder is an exe file called "WirelessCameraConnectionSetting.exe". Double click it and go through prompts, if any.
2) Make sure you've already created a user account on Canon's site.
3) Double-check that your camera is listed as registered under your user profile. I had registered my camera before creating my user account, and so even though I had received an email congratulating me on registering it, the camera was not associated with my user account and it needs to be in order for the "setup web access" through CameraWindow to work. In fact, there's an "additional features" selection called something like "use Canon iMAGE Gateway" that needs to be checked on while registering so that you have established the camera and the ability to use it via the web with your user profile.
Once I'd done all that, it worked just fine. I responded about all this in my customer service feedback survey that they emailed me last night. So hopefully, they'll provide a packaging blow-in or a link on their site. But since I found this forum post by searching CameraWindow Failed To Connect To Server, I'm hoping that if nothing else, others will find this before needing to call themselves.
Hope it helped!
