That page is the one where he eventually gave up and replaced the isapi_redirect.dll with another piece of software, (Last post on the page is by the O.P.)
I have already tried the only substantive change I can find on that page which is to add the full path to the dll against the ps setting in the isapi_redirect.properties file. No effect.
I've replaced the dll with the one downloaded from the Adobe site, which changed the error message briefly until I gave it permissions for Everyone, which reset the error back to this one. This is consistent with several other pages that show this error.
The only other paragraph on there with advice says "I got several things wrong" and then suggests changing the uri setting to match the virtual folder name. Mine already does. I've tried with and without a preceding \. No effect.
I'll try re-doing from scratch.
Is there not a recommended, supported, setup for use of websites in a production environment as proposed by the labs? I'd prefer to be doing that, whatever it is, rather than 'rolling my own'.
Regards,
Iain