winxpとphp4でmbstring使おうとしたんだけどphpinfo()でmstringがでなくて使えないよぉ

[Windows extension]
extension=php_mbstring.dll

[mbstring]
mbstring.language = Japanese
mbstring.internal_encoding = EUC-JP
mbstring.http_input = auto
mbstring.http_output = SJIS
mbstring.encoding_translation = On
mbstring.detect_order = auto
mbstring.func_overload =7

ini-distにこういう設定したんだけどダメなのかい？