...with apache, this is often due to the webserver not
'parsing' the file as a .php file, so the answer there is
AddType application/x-httpd-php .php
in your httpd.conf file, and if you wish to include
php code in .html files, you add that extention as well.
That said, I have no idea in your situation....I've spent
a few years trying to avoid interaction with IIS if at all
possible. 😉
You might make sure that your server knows what
to do with files containing the <?php tag.
Do you get the same result from saving the file with
an .html extension?
Dalecosp