This DLL file may be in use with another program. Deleting it can cause that program to malfunction. The uninstallation wizard of some programs shows the message mentioned above.

The action can't be completed because the folder or a file in it is open in another program. Close the folder or file and try again. This is done for good reason.

If everything else is in working order and you're still getting an "Access Denied" error, Windows likely thinks you don't have the necessary permissions for the file or folder in question.