Server side include problem

I'm about to pull my hair out here.
I have a file called test.asp, which has the following code:
<p>This is test.asp</p>
<!--#include file = "dummy.inc" -->

Then my dummy.inc has:
<p>This is dummy.inc</p>

Running test.asp in one directory will give me expected results:
This is test.asp
This is dummy.inc

Running test.asp in another directory will only give me:
This is test.asp

I have copied test.asp and dummy.inc in both directories.

Anyone have an idea?
Extra info: the two directories are actually two "sites" and I use Expression Web to edit.

 

Never mind...
Finally saw the problem.
I should've gotten more sleep.

If anyone would ever have the same issue:

A setting of my Expression Web was to optimize html and remove all html comments.
Unfortunately that also effects the <!--include file statement

 

Thanks for posting the resolution BertC.