ASP #include file Parent Paths error

Spent almost half a day trying to troubleshoot why some ASP scripts refuse to work when ported over from Windows Server 2003 to Win Server 2008 R2.

Turns out the offending line is this:
<!--#include file="../somefile.inc"-->

After a bit more google-ing, it's obvious that the problem lies in IIS 7.0 and above configuration that set Enable Parent Paths to False by default.

Solution was simple:

Go to IIS Manager, Default Web Site | (feature view) IIS | ASP | Enable Parent Paths = True