Failure to load php_openssl.dll

Hello all, I'm having difficulty getting off the ground with SSL in PHP. With my script | <%php | $res = openssl_pkey_new(); | %> I get this output: | Fatal error: Call to undefined function: openssl_pkey_new() in c:\inetpub\wwwroot\Scratchpad\test.php on line 3 | PHP Warning: Unknown(): Unable to load dynamic library './extensions/php_openssl.dll' - The operating system cannot run %1. in Unknown on line 0 The latter message is clearly closer to the root problem, since I get it even with the trivial script: | <%php | %> Here are the details of my configuration: (1) WindowsXP, IIS. (2) I'm using the precompiled download of PHP 4.3.7. (3) I've uncommented "extension=php_openssl.dll" in my php.ini (which is in C:\Windows\System32). (4) php_openssl.dll is in the right place (php/extensions). I know it's in the right place, because it's in the same directory as php_xslt.dll, which I'm also using, successfully. (5) I've put openssl.cnf in c:/usr/local/ssl What have I missed? Thank-you very much in advance. Angus Monro.