inconsistent php behaviour across different virtual directories

Hi On a server running NT4 SP6 IIS4 and php 4.0.0 I have a virtual directory configured to map various file extensions onto php (cgi version). This works fine. I have created another virtual directory with EXACTLY (yes - honestly - I've checked over and over again) the same configuration for script mappings and indeed everything else apart from the actual directory name and when I try to access a php file within that virtual directory I always get the following error message in my browser. ******** CGI Error The specified CGI application misbehaved by not returning a complete set of HTTP headers. The headers it did return are: ********* This happens even if I redirect my new virtual directory onto the same real directory as the virtual directory which works ok. I realise that the above error message implies that php generated no output (if it even ran). No errors are generated on the server, no entries are posted to any of the logs visible via 'event viewer'. If I remove the script mapping, I get the raw php delivered to my browser. I'm testing with a very simple php file: <?php phpinfo();?> I've stopped and restarted the w3svc and iisadmin services and even rebooted the machine, but to no effect. Has anyone got any clues as to what's going wrong, or any other tests I could usefully perform? Thanks -- Phil Driscoll Dial Solutions +44 (0)113 294 5112 http://www.dialsolutions.com http://www.dtonline.org