Update Field Isn't Working?

I've created a MySQL database that has one table, that table has two fields, the table is called system, the fields are called status and message. The database is used to populate a html table on a page, that works fine.

What I need to do though is have a form on a separate page (which i'm going to add http authentication to) with a simply form consisting of a text box, three radio buttons, and the usualy submit and reset buttons. I need to be able to update the database using this simple form.

However this isn't for adding new records, it is purely for editing the existing record as it's to edit simple warning messages to display to the visitors when there is a problem with one of the systems. The radio buttons determine which light image is displayed (green, orange, red) and the text box for the short message.

However no matter what i try it just in't updating the fields in the database, the following is the html and PHP i'm using: Code: