<object> cannot implement <interface> - it is not an interface

I am getting an error when starting my debugging.
I have a class called as400_database defined like this:

class as400_database extends dbconnection implements db
{
...

in a file called as400_database.php. In a file called db.php I have the definition of db like this:

interface db
{
function connect();
function query($query = false);
function fetch_array($result = false);
function fetch_row($result = false);
function __construct($name,$database='',$username = '',$password = '',$persistent=true);
}

I get the following error:
as400_database cannot implement DB - it is not an interface
If I move the definition of db into the same file as as400_database then it works fine. Before anyone suggests that I simply do that to avoid this issue, I have this typeof thing in a lot of my source and can't change every object I've created just to get past this.

Any other suggestions?
I am using PHP5, Builtin mode, XDebug, version 2,4,4,4494

Thanks
Shane Miller

Comments

    Resolved.....? NOT!

    Well, I started over with the project to see if that helped any and it did! I did a New Project in Existing Folder and now I don't get that error anymore.

    So, then I did it again with a new project and now I get the error with that project. Again, it uses the same files that I got the error in with my initial project so I'm not sure why one gets it and the other doesn't.

    Shane Miller