DirectX 8.1b for Win98/WinMe:
http://download.microsoft.com/download/DirectX/dx/8.1b/W98Me/TW/DX81cht.exe

DirectX 8.1b for Windows 2000:
http://download.microsoft.com/download/DirectX/dx/8.1b/NT5/TW/DX81NTcht.exe