It appears there is a security setting on your server preventing Dreamweaver from posting a SELECT statement. I can reproduce the problem whenever I post to your site with a SQL SELECT statement in the post contents. Unfortunately this is done by a native DW module that I can't easily bypass.
I'm looking into options now, but I won't likely be able to find a simple solution for you.
The update page in your sample only has one problem... for some reason the connection file on the update page is too low on the page. You can manually move the connection require_once statement from lower on the page to the top and then that page will work.
In the all example a lot of code that should be on the results page was added to the update page instead. These issues may be a byproduct of the 406 error. If you run the wizard again with all of the pages do you get the same result? Are there any errors while the wizard is processing?
New from blank probably won't work because it is trying to get the column list, which fails with the 406 error and then you get the other errors when no columns are found.