This is usually due to session state being disabled through the Internet Services Manager GUI.
To enable Session State:
- Open the Control Panel.
- In the Control Panel open the Administrative Tools icon.
- In the Administrative Tools window open the Internet Information Services icon.
- Expand the Internet Information Services tree and locate HelpDesk.
- Right click on HelpDesk and choose Properties from the popup menu.
- Locate the Application Settings and click the Configuration button.
- Click the Options tab and enable Session State.
- Click OK .