If this is Windows 7 (or Vista) this location is not legal. But don't "change it to D:", and probably don't even change permissions. Better use the directories in a legitimate way. Please see my past answer:
How to find my programs directory[
^].
If this is a Web application, you cannot use any directories beyond the directory configures as the root directory for your site. Web applications are run in a sandboxed environment which won't allow access outsize of your project directory tree, regardless of the file system permissions.
—SA