Document Type PHP quite working

am using dreamweaver cs4 runing under window vista.

I have two websites that uses php/mySQL to interact with databases.  Both were built with dreamweaver cs4 on this same computer.  Both have been up and running for some time.

Today I needed to make some changes in one of them.  I loaded a php file in dreamweaver and in the  DataBases panel, instead of listing the databases that this page interacts with, it says...

To use dynamic data on this page:

   1. create a site for this file.

   2. choose a document type

   3. set up the site's testing server.

Also, the +,- symbols  at the top of the panel are grayed out

There is only a check mark in front of #1, Create a site for this file, even though all have been done and all were working properly the last time I woked on this site.

When I click on choose a document type and select php, nothing changes.

If I choose a different type, I get checkmarks in from of all steps and the database +,- symbols are no longer grayed out.

If I go back to document type:PHP, I loose the checkmarks and the +,- symbols gray back out.

The same is true for the other site I have that uses PHP.

Could I have a corrupted file in the Dreamweaver installation?  If so, which one?

All help GREATLY appreciated!

Steve Carroll