Hi, wm2010. Sorry to hear of your troubles. I'm just your fellow Photosynth user and I don't know exactly how to fix this for you, but here's what I can tell you.
The Photosynth app for Windows is being launched when you click the [Create a Synth] button and some network setting on your computer is stopping it from talking to the Photosynth webservice. Which browser you use to launch the Photosynth app makes no difference (You don't have to launch it from the website. You could also use a desktop icon or the Start menu).
If you use a proxy for your internet connection, this has proved to be a problem for people in the past, but unfortunately I don't remember what the correct steps to resolve this are. Hopefully one of the Photosynth team can reply to you and get you up and running soon.