Yeah that's the correct syntax, except remove the
.. so it looks like
Code:
<!--#include virtual="/forums/admin/active.inc.php"-->
otherwise it will try to go up one directory before looking for the "forums" directory. Assuming the forums directory is right below the root, i.e.
Code:
root [aka yoursite.com/]
--> forums (subdirectory) [aka yoursite.com/forums/]
it will work just fine.