I have tried everything, but just can't figure it out.
I am trying to make the timthumb.php file work, but I just can't access the file on my server through the absolute URL. In fact, I can't access any PHP file in the root directory that WordPress is installed in other than index.php. Accessing any other php files in the root which I know are there (e.g., header.php, footer.php) all result in WordPress throwing a 404 error message.
I'm sure this is something simple, but I just can't understand why WordPress won't open a PHP file which exists and instead throws 404 error messages. Browsing the blog through categories, search, posts all works fine.