Dear ropu,
Thanks for the snippet. So this is the array I see now, no Merchant ID or key in sight.

Code:
 
Array ( [PATH] => /usr/local/bin:/usr/bin:/bin
[CONTENT_LENGTH] => 2607 
[CONTENT_TYPE] => application/xml 
[DOCUMENT_ROOT] => /home/sally/public_html 
[HTTP_ACCEPT] => application/xml 
[HTTP_EXPECT] => 100-continue 
[HTTP_HOST] => www.roll-over-rover.com 
[REMOTE_ADDR] => 74.52.178.162 [REMOTE_PORT] => 41554 [SCRIPT_FILENAME] => /home/sally/public_html/store/googlecheckout/responsehandler.php [SERVER_ADDR] => 74.52.178.162 
[SERVER_ADMIN] => [email protected] 
[SERVER_NAME] => www.roll-over-rover.com 
[SERVER_PORT] => 80 
[SERVER_SOFTWARE] => Apache/1.3.37 (Unix) mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 FrontPage/5.0.2.2635.SR1.2 mod_ssl/2.8.28 OpenSSL/0.9.7a PHP-CGI/0.1b [GATEWAY_INTERFACE] => CGI/1.1
[SERVER_PROTOCOL] => HTTP/1.1 
[REQUEST_METHOD] => POST 
[QUERY_STRING] => [REQUEST_URI] => /store/googlecheckout/responsehandler.php 
[SCRIPT_NAME] => /store/googlecheckout/responsehandler.php 
[PHP_SELF] => /store/googlecheckout/responsehandler.php [argv] => Array ( ) [argc] => 0 )
I've been reading up on PHP as CGI rather than Apache - and that 'PHP_AUTH_USER' isn't available? I know some PHP, but I certainly don't know squat about server configurations, so I'm lost here. I'd like to figure it out though. I'm sure others may have this problem in the future as well.
Thanks