Cannot find ODBC32.dll

I am using Win98. I have installed PHP-4.3.4-Win32. When I tried to run php.exe, Windows printed a message "Cannon find ODBC32.dll". I really didn't find that file on my computer. I tried an older PHP-3.0.17, but with the same result. I read that PHP since 4.0 has built-in ODBC support so I don't know why is my system asking for such a thing. The only change that I made to php.ini was changing extension_dir. I was searching for the file "odbc.dll" on Win98 instalation CD but that file wasn't there. What shall I do? -- Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/