Web/CS - HTTP 500 error Microsoft VBScript runtime error '800a01f4' Variable is

Resolving The Problem

Web/CS - HTTP 500 error Microsoft VBScript runtime error '800a01f4' Variable is undefined: 'Session' /IDMWS/home.asp, line 20
Software versions Windows 2000, NT 4.0, IIS 4.0, IIS 5.0, IDM Web Services 3.1

Steps to verify if problem applies:
When accessing the website, an HTTP 500 error is displayed. Since the error is vague and a common error is IIS, disabling "Show friendly HTTP error message on the IE browser (Tools/Internet Options/Advanced Tab/Browsing/Show friendly....) produces a more descriptive error "Microsoft VBScript runtime error '800a01f4'
Variable is undefined: 'Session' /IDMWS/home.asp, line 20

Steps to resolve problem:
1. Right click on IDMWS virtual folder and select "Properties"
2. Click on "Configuation" in the Virtual Directory tab.
3. Click on App Options tab
4. Make sure "Enable session", Enable buffering, and Enable parent path" is selected and "Default ASP language is set for VBscript.

If "Show friendly HTTP error messages" is enabled on the IE browser, an HTTP 500 error is iniatially shown.