Yes, all type="url" gadgets are returning 404 errors in the Orkut
sandbox at the moment. The good news is that is a known issue that
should be resolved shortly.
Type="url" applications are limited in that you can't make use of the
existing OpenSocial JavaScript API, which severely limits your
application's social reach. You do have a few additional options,
however. For example, you can set up your PHP script to access your
MySQL database and return record information in an XML- or JSON-based
response. Then, in a type="html" app, you can use the
gadgets.io.makeRequest() method to fetch this response from your
server and display it. The beauty of this approach is that it's
flexible and affords you the ability to use the opensocial API to its
fullest.
Please let me know if you have any more questions.
- Jason