I have one computer on which the Select Files button doesn't do anything when clicked. By right clicking, I can tell that it is using Flash, and I made sure I have the newest version of Flash Player. I don't have any other issues with Flash. I have another computer on which the button does work, and it is using Silverlight.
I also have a few clients for which it doesn't work, and I don't want to have to require them to install Silverlight. Since I don't need the ability to upload multiple files, I would like to simply use the IFrame uploader, which works, but there is no progress bar visible. Should there be? Is there anything special I need to do on the page to get the progress bar to display?