Yes, there seems to be something wrong with the recordset. On the detail page, when I look under server behavior, there is a little red exclamation mark next to the record set "DetailRS1". That is the record set that is created by dreamweaver when I use the "master detail page set". On the detail page, dreamweaver puts all the info in the non-editable region. Maybe that is the problem. Right from the start, before even making a single change to the page, that little exclamation mark appears.
I deleted all the pages (catalog, detail and cart) and created them new, and for now it is working again.
When I double click on the record set behaviour, and hit OK in the record set window, the exclamation mark goes away. But when I then try to open the page in the browser, this little uplifting message appears: "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1"
I will do more testing in the morning, and try to reproduce the error.