building a simple extensin failed because lack of libxml

Hi, I'm new to PHP. I'm trying to learn how to make PHP extensions on Windows, and followed instructions in Chapter 5 "Your First Extension" in "Extending and Embedding PHP" by Sara Golemon with a few modification necessary to suit for Visual Studio .NET 2003 environment I'm using. I could manage to build the PHP core. But when I tried to build the most simple extension which only has an extension entry, I encountered a compilation error: C:\PHPDEV\php-5.2.0>nmake php_sample.dll Microsoft (R) Program Maintenance Utility Version 7.10.3077 Copyright (C) Microsoft Corporation. All rights reserved. sample.c internal_functions.c c:\VS2003\Vc7\PlatformSDK\Include\WS2tcpip.h(647) : warning C4142: benign redefinition of type c:\PHPDEV\php-5.2.0\ext\dom\php_dom.h(33) : fatal error C1083: Cannot open include file: 'libxml/parser.h': No such file or directory NMAKE : fatal error U1077: '"cl.exe"' : return code '0x2' What I don't understand is why building this null extension requires building the dom extension. I would like to know: (1) Can I simply tell the configure (or build system) not to worry about DOM extension? If so, how? (2) Where am I supposed to insatll libXML, if I really need this? (Or how am I supposed to tell the build system where it can find libXML?) Thanks in advance. -kuro