had a look at your ASP page source code and actually seen the line:
This should not be the case. If i view the source it should just be HTML where the include file is. Now there are a number of reasons why this has happened. Maybe you have the following code:
This would not work.
An include file doesn't go within <% and %>. Remember you may have more ASP code in your include so you would have <% from your current page then followed my any <% and %> in your include, then you are doing %> back in your current page. This will not work.
Just try this:
'whatever asp code here
'the rest of your asp code
Failling that have you tried using virtual inc file?
<!--#include virtual ="default.asp"-->
If it still isn't working please post the code for the page.
Hope this helps