Hi,
I'm also getting the same problem and its driving me nuts. I've searched the forum for the solution, but it appears that I've done everything exactly the same.
I'm using PHP5.0.1, IIS 5.1, WinXP Pro (without SP2) and MySQL 4.0.
What I've done:
Uncommented the line extension=php_mysql.dll
Changed to extension_dir = "C:\svr\php\ext"
I installed PHP5 in c:\svr\php.
Copied libmysql.dll to c:\windows\system32
Added "c:\svr\php;c:\svr\php\ext" to the PATH environment.
I'm still getting UNDEFINED FUNCTION error.
Anything I'm missing here or did wrongly? Thanks.