I'm trying to get PowerPoint 2007 to export html that does not require ActiveX and does not cause any warnings to show up in the browser when it loads. Is this possible?
You cannot control the PowerPoint output to exclude ActiveX, etc.
The best way for you is to export your presentation to pictures, and then embed them into HTML page(s) (I recommend the Lightbox JS plugin, then you can go forward and backwards nicely).
If you are willing to pay, there are also 3rd-party software to convert your presentations to web. How well they work though I have no idea.
The third, and maybe better way, to put your presentation on the web is to use GoogleDoc's Presentations function. Upload your presentation, and let GDocs render it to be a very capable web presentation.