Many scripts use a function called parent paths.
If you are running one of these scripts and find after checking logs that you see entries like "'ASP 0131' Disallowed Parent Path" the you would need to enable the use of parent paths for your domain.
This feature is not enabled by default however it is easy enough to enable. To enable parent paths you would follow the steps below:
1. Login into plesk
2. Click on Home on the left menu.
3. Click on your domain name (center window)
4. Click on Web Directories Icon
5. Click on Preferences
6. Check the box to Enable Parent Paths.
7. Click OK and your done.