php5activescript mostly works but odd gaps

I am involved in getting an application running to allow web sites with
script pages to run off CD. It has worked with ASP for years (Dynamic-CD)
but we want to get php in there as well. We have put in the dll and fiddled
about with a bit of parsing and it nearly all works but with a few critical
bits missing. It's probably something obvious I need to put in the
php-activescript.ini or add in and recompile the dll.

Here are the symptoms:

$_SERVER, $_GET, etc are all blank although the $_ENVs seem to be there.
session variables are being written to the \Program Files\PHP\sessiondata
directory as specified but are not available to chained script files.
some functions such as echo and phpinfo work but nothing is output. However
if I ob_start(); phpinfo();// or echo something;
$Response->Write(ob_get_contents());
everything is fine!
May not be relevant but I am running the scripts and parser programs on C:
drive although I am logged in and working through MSVC++ on I: (some of the
debug stuff is hard coded to C:)

Paddy