Weird com object behaviour on W2k3

[pigwin32]

I have an asp application that uses a javascript server side include to
instantiate a component for generating our menu html. The component is
pooled and worked perfectly on Windows 2000.

On Windows 2003 the behaviour is quite weird. For non-ssl traffic the
component is instantiated and I can call the getMenu() method. Once the
page is rendered by the server the object is released back into the
pool. There is a getLoginMenu() method that returns the html for the
login menu. These pages require SSL and again the component behaves
correctly. But once logged in to the secure SSL pages the component
isn't released back into the pool when the page is rendered, so the
pooled component count just keeps going up until the maximum is reached
at which point everything stops until a timeout occurs.

Setting the object to null at the end of each page does actually fix
the issue but would require changing every page and introduces the
possibility that it could easily be overlooked if a new page is added
to the site.

The C++ source for each of the methods used to generate a menu is
practically identical, it uses an xsl transform to generate the html.

Any clues gratefully received.