dl() doesn't work . PHP 4.3.1 + Apache 1.3 + Win2k.

Hope to find someone to help me with this: I am trying to load a dynamic extension using the dl() function. The dll file resides in my web root directory (c:\inetpub\wwwroot). I have extension_dir = ./ in php.ini (the default). dl("xxxx_php.dll") doesn't seem to find the file when called from a script that resides in the same directory as the extension file (xxxx_php.dll). Also, I've tried setting extension_dir = c:\inetpub\wwwroot without success. Any ideas, please? Thanks in advance.