Extension loading problem

I'm running IIS 5.0 on a Win2k pro. Machine using PHP 4.0.6 I want to enable support for MSSQL 2000 but I can't get the extension directory path to work properly. Right now, I've copied php_mssql.dll in "c:\php\extension_dir" and "c:\php" and also in "c:\WINNT\system" I have the line in php.ini set to : "extension_dir = "c:\php" I've also used "c:\php\extension_dir" as well as "c:\WINNT\system" as well as "c:\%systemroot%/system" I have no idea what else to try to get it to find the dll file, but I always get the same response: "Unable to load dynamic library 'C\WINNT\system\php_mssql.dll' - The specified module could not be found." I appreciate any help in this, thanks in advance. -Rob