Enabling parent paths specifies whether an ASP page allows paths relative to the current directory (using the ..\ notation). If set to true, this property constitutes a potential security risk, because an include path could access critical or confidential files outside the root directory of the application.
In IIS 6.0, parent paths are no longer enabled by default. This affects your application if it has a Web page that contains the #include server-side include directive and uses “..” notation to refer to a parent directory. Enabling parent paths corresponds to the meta-base setting….
To enable parent paths
1. In IIS Manager, double-click the local computer, right-click the starting-point directory of the application you want to configure, and then click Properties.
2. Click the Directory tab, and then click Configuration.
3. Click the Options tab.
4. In the Application configuration section, select the Enable parent paths check box.
5. Click OK