SubInACL is a command-line tool from the Windows Resource Kit that can be used to update file, folder and registry permissions, and can help fix some Access Denied errors that can be encountered while trying to install products, hotfixes and service packs on Windows. It enables administrators to obtain security information about files,
Request approved, user can access the folder The user signs out, signs back in and can access the folder which previously caused an "Access Denied" error. On Windows, changes to a user's group memberships only take effect when the user signs into his PC. This means that after the user was added to the group in question, he must sign off and sign back on before he can access the protected share, folder, etc.
first check if the file or folder is in use. Close all open files and folders and try again. If it does not help, Take Ownership of the file or folder and see if you are now able to delete it. If even this does not help, check if you have the proper File and Folder Permissions.