Comments by The Myth (Top 1 by date)

It's been awhile since I did any mysql coding. A few questions to narrow things down:
- I assume the select statement works? So you know your connection string is working?
- I see two inserts. Do you know which SQL insert is not working? Do you know the actual SQL string or variables it is trying to insert? That way you can test them against the database directly to verify they work without the PHP code.
- Did you verify through the firefox's web console that there is no javascript errors or through HTTPWatch to see the ajax response that you are getting back from the server? Once you know this, you can test this directly outside of the page itself.

Once you can narrow down which piece is having the issue, it will be a lot easier to solve. I noticed you're using a lot of onclick, onfocus, onmousedown events in html, you should try to avoid these and have all that logic in the javascript by using jquery's onclick events instead. Also you're using XMLHttpRequest directly which probably isn't cross-browser compatible. Again, I would use JQuery for this logic. Have you tried this in multiple browsers? It might work in some and not others if the issue is ajax related.